In this chapter, I will defend and explain my item choices as presented above.
Tangos heal you, and heal your tethered teammate. Tangos last for 16 seconds and Tether lasts for 12, so try to make sure you're Tethered for most/all of the duration.
Ring of Protection
Increases Io base armor from 0 to 2, which is 11% physical damage block. Io has naturally 0 Armor and gains 3 Armor by Lv 12 (some of the worst armor gain in the game), so this opening item is key for laning phase survival. Ring of Pro builds into Tranquils later on.
Minor stat boost, and builds into Wand. Can be eaten with Tango for extra HP boost.
Mango increases your base HP regen from 0.8 to 1.8. This TRIPLES the strength of your passive Tether heal, healing a teammate for +3 HP/sec (as compared to +1 HP/sec without Mango). Consume Mango when desperate for free Spirits cast.
This will help to replenish mana spent in the first few minutes of the game, from Tethers and potentially early Spirits casts. Tethering to a teammate will give them explosive mana gain. I often use as/before Soul Ring is coming on the courier.
This is not Bottle. Why is there no Bottle?!?
Bottle is a fine item on Io. The early HP and MP regen are great for attempting kills in the first few levels of the game, depending on your lane partner ( Slardar is a great example). However, Bottle contains a max of 3 uses, and relies on two methods of refilling: Runes, which can be contested or taken by enemy players, or going back to your Base (or giving your Bottle to a player who just recently came from the Base and still has the Base refilling buff). Both of these options require you to LEAVE THE LANE, whether this is to get Runes or run/teleport back to your Base. This drains Io of valuable experience, denies, stacking opportunities, and even last hits, which are crucial in the early laning stage. If Io buys Bottle, he is totally reliant on that item to do anything. He has no stat items, no armor or damage, no passive regen, no consumable regen other than 2-5 Bottle charges every 2 minutes.
Not only that, but the regen from Bottle (even when magnified through Tether onto your teammates) is only strong for the first several levels of the game when compared to other item choices. Bottle can heal another hero for ((90 HP * 3 charges) * 1.5 tether boost) = 405 HP with 3 charges every 2 minutes. Tranquil Boots can heal in 30 seconds of Tether (((0.8 base HP regen + 12) * 1.5) * 30 sec) = 576 HP, and that's without any other regen items. Bottle can restore ((60 MP * 3) * 1.5)= 270 MP to tethered ally with 3 charges every 2 minutes. Soul Ring delivers more than four times this mana output, with ((150*1.5) * 4)= 900 MP every 2 minutes to Io's Tether targets.
Finally, if Io were to buy Bottle - which is still a great item, depending on your lane hero - he would buy different items in a different order when compared to this guide. The core principles described in the "How to use Tether/Spirits/etc." sections are still useful for any Io player.
I feel the items described are a more broad-spectrum approach to playing Io, and are easier to master for most players.
(1) Soul Ring
Soul Ring is a more stable mana-replacement item than Bottle. With this item, you can generate 150 MP every 30 seconds for yourself, which is 225 MP for your Tethered partner. You must spend the 150 MP before the Soul Ring buff ends (10 seconds), but your Tether partner is not effected by this rule. Through this method, Soul Ring can generate up to 900 MP every 2 mins (225 * 4 Soul Ring uses) for your Tether buddy.
Soul Ring is best combined with low-mana carry heroes that have short-cooldown stuns or damage spells. Sven, Luna, Chaos Knight, Legion Commander, Bristleback, Phantom Lancer, Necrophos, Pudge, Tiny are good examples.
The 150 MP from Soul Ring is also exactly the cost of a Spirits cast (at max lv). Therefore, Soul Ring is best used by (1) Tether to target (2) use Soul Ring, giving you 150 MP and partner 225 MP (3) cast Spirits for 150 MP, losing 0 net mana. Buying Soul Ring allows Io a far greater freedom to use Spirits, Io's main damage spell, at a high frequency compared to other early game items such as Bottle.
Soul Ring also increases your passive HP regen/sec by +3. Tethering to another target will heal them for approx. 7-8 HP/sec, which is the same rate as a consumed Tango!
Another minor use of Soul Ring is to lower your HP - on purpose - in order to passively heal a Tether target. Normally Io's health is lowered with Overcharge, but this is an extremely inefficient way of doing so because of the large amount of MP lost relative to HP. Using Soul Ring instead is far more constructive to your mana pool.
When building Soul Ring, you can purchase Sage's Mask from the Sideshop, which combines with your Ring of Protection to form a temporary Ring of Basilius that can be disassembled at any time. The bonus attack damage from Ring of Basilius can help you secure last hits and harass the enemy more effectively until your Soul Ring Recipe arrives from the courier.
Most importantly, Soul Ring is the ONLY mana item you need for the entire game. Once you reach Lv 15 and choose the +10 Mana Regen talent, Soul Ring can be sold to open a slot for a new item.
(2) Tranquil Boots
Using Soul Ring hurts, so to recover your HP, we purchase Tranquil Boots next. This increases your HP regen by +12 and incorporates your Ring of Protection for +3 Armor. Now, you can help your carry recover both HP and MP, allowing you both to dominate the laning phase and feel more comfortable initiating kills. The +3 armor translates into an additional ~13% physical damage block over his natural armor
When Tethering to a target, HP regen for them is now above +25 HP/sec. A Tether lasts for 12 seconds, meaning you can heal a Tether target for up to 25 * 12 = ~300 HP in a single Tether (by keeping your HP <100% and not taking any enemy hero damage). Changing your auto-attack settings to "Never" is a smart way to prevent Tranquil healing interruption, especially during teamfights when keeping your carry alive is crucial.
This also means you can essentially spam Soul Ring activation without fear of self-damage, giving yourself free mana to cast Spirits or Relocate and keeping all other players topped up on mana.
(3) Magic Wand
Now that our Soul Ring/Tranquil Boots combo is complete, we need Io to get stronger. At this point he is all regen and no stats. Wand provides a much-needed stat boost to Io, as well as provides another quick-activation healing item which can be used while Tethering to a target.
(4) Urn of Shadows
Urn of Shadows provides more stats for Io survival (+6 Str helps our damage, too), but the real profit comes from the use of the Urn charges. Urning yourself and Tethering (while Overcharging) to a hero in a fight can heal them for up to 600 HP (as long as you don't take any enemy hero damage). This makes Urn a powerful healing spell that is crucial to Io's mid-game healing functionality. Urning enemy players can net you crucial kills (with its long range and Pure damage) and can help increase your DPS in teamfights.
Because of this, Io should have priority on the team to purchase Urn of Shadows over other heroes who normally have Urn in their item builds (such as Huskar, Pudge, or Spirit Breaker).
(5) Glimmer Cape
At this point in the game, many players will think of running for a Mekansm or another team-healing item, when in reality, you need to think about keeping yourself alive. A dead Io is not a helpful Io. A many-times-dead Io will get you reported.
Glimmer Cape is the best escape item for Io in the game - bar none. The 15% Magic Resistance is stronger than your Lv 10 Talent, and the +20 Attack Speed is a nice bonus. Glimmer can be activated on yourself OR ANOTHER HERO to make them invisible for 5 seconds. This is HUGE and can be used in a variety of ways, from dropping aggro on a focused teammate to invs-ing yourself and TP-ing to safety. Glimmer Cape can be activated BEFORE Relocates and Returns, allowing you 4 seconds of safety to escape while the enemy stand around confused. Glimmer Cape can also be used for its 45% Magic Resistance, which can be cast on yourself or others to block damage from incoming magic attacks (such as Invoker Chaos Meteor or Necrophos Reaper's Scythe).
Glimmer Cape can also be disassembled at any time, which means Io has access to a Shadow Amulet. Splitting Glimmer Cape into Shadow Amulet during a Relocate escape, and using Shadow Amulet to invs yourself before your Return to combat (Shadow Amulet invisibility does NOT BREAK upon Relocate Return) has saved my life many, many times. It also looks f*cking badass.
Glimmer Cape is countered by several heroes. Slardar and Bounty Hunter can mark you with their Ultimates, so going invisible will not work. Bloodseeker provides vision if you're at low health through Bloodthirst, and Zeus' lightning bolt will temporarily show your location as well. 95% of the time I would build Glimmer cape, except against 2 or more of these heroes.
These items should be completed by the 15-20 minute mark (15 mins in a fast game with early kills, 20 mins in a slow game with early deaths). My personal best is just under 12 mins.
These items are not necessarily in order of purchase. A smart player will need to assess his enemy team and his own situation to understand what items are best to purchase next.
Unless you are doing amazingly well, Mekansm is the next logical item for Io. This provides armor, some minor stats, and a group heal for +250 HP. Through Io's Tether (presuming he gains the full 250 HP and is not at 100% HP at the time of casting), Io's Tether target receives the Mek heal of 250 HP AS WELL AS the 1.5X Tether heal from Io's 250 HP gain. This equates to (250 + 250*1.5) 625 HP gain on a single Tethered hero.
What's a great way to ensure Io has less than 100% HP when he uses Mek? Use Soul Ring to supplement the 225 mana cost of Mek activation!
Pipe of Insight OR Crimson Guard
Pipe/Crimson is a great way to increase Io's base HP regen even further, while also blocking incoming magic/physical damage to yourself and your team.
I would almost never buy BOTH of these items, but would try to assess from the enemy team's picks and best heroes what type of damage I should be most scared of (3 or more Magic Heroes? Pipe of Insight. 3 or more Physical Heroes? Crimson Guard.)
Heart of Tarrasque
For the longest time, I thought HoT was just too expensive to be viable. With its heavy pricetag, why spend so much money on a healing item that stops working as soon as you take damage?
Oh, what a fool I was.
HoT, especially after the 7.00 updates (where its regen has been increased from 4.5% HP/sec to 7% HP/sec), is without a doubt THE DEFINING ENDGAME ITEM FOR IO. If you can get your hands on this item, the game is borderline over. By staying behind your team's lines and Tether/Overcharging heroes taking damage, you can swing teamfights in your favor, support pushes by recharging half-health heroes, and even tank tower damage without flinching.
Tether healing with HoT heals your target for upwards of 200 HP/sec, and that's limited because OVERCHARGE DOESN'T TAKE AWAY HP FAST ENOUGH (Overcharge bleeds 4.5% HP/sec, HoT heals you 7% HP/sec). If you are damaged and can heal at the full rate HoT allows, you will be healing a Tether target for upwards of 270 HP/sec. Greater than 1 Mekansm activation PER SECOND. That's how f*ckin insane this item is.
If I am having a particular strong game from the laning phase onwards, I will skip Mekasnm + Pipe/Crimson and rush right for HoT. A 25 minute HoT wins the game. Every time.
The HP boost and Str bonus from HoT build into Io's damage and max HP, putting him somewhere around 2500 total HP. If you are attacked and HoT deactivates, Glimmer Cape is available to hide and reposition, giving HoT time to reset and activate again.
Ziqi, the #1 Io in the world, swears by HoT. His endgame strategy is Heart of Tarrasque --> Black King Bar --> Octarine Core. BKB allows Io to escape being pinned down by CC, and the Octarine Core actually reduces the time it takes for HoT to activate again after deactivation (from 8 seconds to 6).
Around 26-32 minutes, I am hoping for EITHER:
(1) Mekansm + Pipe of Insight OR Crimson Guard (total 5575 gold OR 5925 gold)
(2) Only Heart of Tarrasque (total 5500 gold)
Boots of Travel
BoTs are a great item for when the game is almost over. I will often buy BoTs as my last item before the game ends, in order to keep up with the team pushes and stay near the carry to heal him. I only EVER buy BoTs after I have my healing items purchased. The bonus move speed helps keep Io alive and unpressured, and the reduced TP cooldown increases Io's mobility to extreme lengths.
These items are RARELY PURCHASED. I am discussing them because they are present in my in-game build, as reminders to watch for situations that would call for them.
When Glimmer Cape's effectiveness is threatened by other enemy heroes, Force Staff can help supplement Io's ability to keep himself and others alive. Force Staff yourself or others out the reach of enemy heroes, which combined with Tether 13-16% run speed boost and a Glimmer Cape for additional invisibility (and a Relocate escape in your back pocket), Io becomes a sort of "puppet master" in the game, moving heroes and hiding them as he pleases. The +4 HP/sec is a nice bonus for passive Tether healing, and the Intelligence is a boost to your MP pool that certainly doesn't hurt.
Force Staff can also be upgraded into Hurricane Pike with many benefits for Io, including a reduced FS cooldown (from 20 seconds to 15) and additional attack range, with 300 HP + 15 damage from the Strength and +20 attack speed + 3 armor from the Agility.
However, I see two major drawbacks of Hurricane Pike. First, the cost of this upgrade is another 2500+ gold, which might be better spent on another item or more advanced healing items. Second, Hurricane Pike does not allow you to FS push the enemy FORWARD, only backward. There are situations where FS pushing enemy heroes as they walk towards you can put them out of position for an easy kill. Io does not have much melee damage in this build, so the Hurricane Pike backwards push would be more defensive than offensive. As a result, Io is only able to make partial use of this item.
Ghost Scepter is a third "hero avoidance" item, along with Glimmer Cape and Force Staff. The increased magic damage you take during Ghost Scepter activation means this item has its pitfalls and is only useful against specific melee heroes who are giving you trouble in the game, such as Clinkz, Ursa, or Huskar. Ghost Scepter is used as an escape item, by buying time for the next Relocate/Glimmer Cape/Tether/Heal/Teleport.
There are games in which Io's Relocate ability makes him a prime pushing agent. Tethering to another player and Relocating to a tower to push for 12 seconds before Returning to safety can upset enemy player positioning and ultimately win games. Deso is a great pushing item that should only be bought in dire situations where your team is stalling against enemies with strong base defense. The armor reduction works on enemy structures, and will help you to push towers and rax in a short period of time.
Veil of Discord
Veil makes an excellent mid-game Io item that I've only seen bought by incredibly high-skill players. The stats on this item complement Io very well, including +6 armor, +6 HP regen, and a good set of stat buffs (+6 Str, +6 Agi, +12 Int). The 25% magic weakness debuff is great for increasing Spirits damage, but more importantly, it can also increase magic damage from the rest of your team. This item does not scale well into the late-game, so I would only purchase it in game you are already winning, or on a magic-focused team that does not already have a Veil purchased by someone else.
This is one of the more interesting situational items, and not for the reason you may think. The reflective shield can be useful against targeted spell-casting enemies, but the real genius of the item is in the rulebook.
Lotus Orb is the only item in the game that acts as a Basic Dispel you can cast on ANOTHER HERO. All other Basic Dispel items are self-cast ( Eul's Scepter of Divinity, Guardian Greaves, etc.), but Lotus Orb's short cooldown and ability to remove debuffs from other players makes it seem like a viable item for circumstances where your team is getting bogged down in slows, roots, silences, and some DoTs.
Lotus Orb is best against the following enemies:
Crystal Maiden --- Crystal Nova slow, Frostbite root, Freezing Field slow
Drow Ranger --- Frost Arrows slow and Gust silence
Earth Spirit --- Rolling Boulder slow, Geomagnetic Grip silence, Magnetize DoT
Enchantress --- Untouchable and Enchant slow
Lich --- Frost Blast slow, Ice Armor debuff, Chain Frost slow
Meepo --- Earthbind root and Geostrike debuff
Naga Siren --- Ensnare root and Rip Tide debuff
Night stalker --- Void slow and Crippling Fear silence
Phoenix --- Fire Spirits debuff/DoT and Icarus Dive debuff/DoT
Silencer --- Arcane Curse DoT, Last Word debuff/silence, Global Silence silence
Skywrath Mage --- Concussive Shot slow and Ancient Seal silence/debuff
Treant Protector --- Leech Seed slow/DoT and Overgrowth root
Warlock --- Fatal Bonds debuff, Shadow Word debuff, Upheaval slow
THIS SECTION IS STILL UNDER CONSTRUCTION
ITEM DEBUFFS OF INTEREST -
DUST debuff, Orchid/Bloodthorne silence, Eul's Cyclone, E-blade debuff, Diffusal Purge, Rod of Atos root, All Maims (Sange, S+Y, Heaven's Halberd), Scythe of Vise hex, Veil of Discord debuff, Solar Crest/Medallion of Courage debuff, Shiva's AOE slow
SPELLS OF INTEREST (that are end-game relevant) -
Arc Warden Flux, Bane Nightmare, Batride Sticky Napalm, Bloodseeker Bloodrage and Bloodrite, Brewmaster Thunderclap slow, Bristleback Viscous Goo slow, Dark Seer Ion Shell, Death Prophet Silence, Ember Spirit Searing Chains root, Faceless Void Time Dilation, Keeper of the Light Mana Drain and Blinding Light debuff, Lifestealer Open Wounds, Lion Hex, Lone Druid Savage Roar debuff, Phantom Assassin Stifling Dagger slow, Puck Waning Rift silence, Shadow Shaman Hex, Timbersaw Whirling Death debuff and Chakram slows (1 while moving, 1 while stationary)
ULTS OF INTEREST -
Bounty Hunter Track, Centaur Warrunner Stampede slow, Dragon Knight Ult Breath, Elder Titan Earth Splinter slow/disarm, Gyrocopter Call Down slow, Sand King Epicenter slow, Slardar Corrosive Haze, Templar Assassin Psionic Trap slow, Tusk Walrus Punch slow
Solar Crest is a nice item - in theory. It provides evasion, which is great for Io's survival from physical carries, and can be activated to buff teammates or debuff enemies. My issue with Solar Crest is the introduction of many evasion talents in the 7.00 patch - this has increased the use and purchase of Monkey King Bar, which NEGATES most of Solar Crest's functionality. One MKB on an enemy team carry means you've all but wasted almost 3000 gold. As a result, I would only purchase it in games that we were already winning very aggressively and were going to end before any enemies could save enough to buy an MKB.
Guardian Greaves - I DO NOT LIKE GUARDIAN GREAVES
Before 7.00 talents, Guardian Greaves were necessary on Io. Advancing your Mekansm into a Guardian Greaves would stabilize your mana pool for the late game, alongside the use of Soul Ring.
Now that the +10 Mana Regen talent exists, Soul Ring can be sold and Guardians have become relatively ineffective on Io. Guardians now represent a reduced Mekansm cooldown (from 70 sec on Mek to 40 sec on Guardians). Giving out mana to your team - that's what Io does anyway through his Tether - so spending 3000 gold on Arcane Boots and the Guardian's recipe doesn't seem like a good use of money anymore. I'd rather spend the 3000 gold on Pipe or Crimson for the specialized damage block and increased stats/regen.
It is worth mentioning, however, that Guardian's activation works as a Basic Dispel upon yourself, and will remove a variety of debuffs.
Vanguard/ Crimson Guard/ Linken's Sphere
Rush Vanguard/Crimson against Legion Commander in an attempt to slow down his successful duels. Linken's is theoretically your best choice, but the cost is extremely prohibitive.
This is included as a Glimmer Cape replacement. In case I faced several heroes who would disrupt Glimmer Cape (BH, Slardar, etc.), but Mekansm was already being bought by another teammate, I would keep Vladmir's Offering as a potential option.
Eul's Scepter of Divinity
I hardly ever buy this item. I think it is overpriced for what it offers (especially as Io has no need for bonus mana or mana regen). However, in certain hero situations (such as being against KotL's Mana Drain), casting Cyclone on yourself acts as a Basic Dispel that will remove a variety of debuffs.
Wanna skip reading this section? Well then this is all you need:
(1) At lv 5, your skills should be 1-3-1
(2) Max Spirits first
(3) Then max Overcharge
(4) Then max Tether
Io's skill build is relatively standardized.
There are differences of opinion about what skills to increase on Lvs 2-4, but the controversy is very minor. Do you level up 2 points in Spirits by Lv 3, or 1 in each skill by Lv 3, and do you put 1 point in Overcharge before any points in Spirits, etc etc etc.
By the time you're Lv 5, your skill build should be 1-3-1. You can take whatever path you'd like to get there, but as long as you're leveling up Spirits first and have 1 point in Tether and 1 point in Overcharge at Io Lv 5, you're doing fine.
If you're lv 5, and your build is NOT 1-3-1, you're doing it wrong. 100%, no questions asked, completely, utterly, wrong. I'm sure this statement will upset SOMEONE when they read it, but it's the unfortunate truth. You can watch any professional Io game from the last 18 months and every single player levels Spirits first, then Overcharge, then Tether. It's the equivalent of not leveling up Dark Seer's Ion Shell first, or not leveling up Pudge's Hook first.
Why rush Spirits first, as compared to Overcharge or Tether???
Spirits is Io's bread and butter. Spirits at Io lv 7 (when Spirits is lv 4) provides 500 magic damage (5 orbs x 100 damage), which is STRONGER THAN A LV 1 LINA ULTIMATE with a cooldown of 14 seconds.
Leveling up Spirits increases the damage of the orbs by the same amount at every level. It is a 100% increase in strength per level. 1st level is 25 damage per orb. 2nd level is DOUBLE that. 3rd level is TRIPLE that. 4th level is QUADRUPLE that. That is a 400% increase over 4 levels.
Leveling up Overcharge only increases the Attack Speed stat by 25% of the original per level (Lv 1 = 40, Lv 2 = 50, Lv 3 = 60, Lv 4 = 70). That is a 75% increase to Attack Speed over 4 levels (vs 400% if you leveled Spirits). The damage block DOES quadruple in strength like Spirits damage (5-10-15-20), but this does not get you kills in the early game and only improves defense. Even if you are supporting a carry who benefits from the Attack Speed and Damage Reduction bonuses, you are still doing yourself a disservice by not investing in your most powerful spell, Spirits.
And don't even get me started on leveling up Tether...the returns are very sad indeed.
If I see another Russian youtuber put 3 points in Tether by lv 5, I will scream.
Tether allows you to heal a teammate by 1.5x your MP and HP regen. If you are healing for 20 HP/sec, your target will be healed for 30 HP/sec.
IF YOU ARE NOT GAINING HP OR MP, YOUR TARGET IS NOT GAINING HP OR MP. If you heal yourself while you're at 100% HP, and do not physically gain any new HP points, then your target will not receive them either. Overcharging to lower your health <99%, or taking creep damage, or using Soul Ring are all ways to ensure this does not happen. This is less of an issue with MP regen, because the act of casting Tether on a target is enough to lower your MP below 100% (paying the 40 MP cost to cast Tether) so that your Tether target is basically guaranteed some level of MP regen.
Urn, Wand, Bottle, and Mek are active ways of healing yourself to help heal others. Tranquils, HoT, and other passive heals (such as activated Fountains) are also viable options for healing (and often overlooked).
Tether's cooldown is 12 seconds and Tether lasts for 12 seconds. THAT MEANS - if you break Tether early (accidentally or on purpose) you must wait until the remainder of the cooldown has finished before casting again. When you are Tethered and healing another player, ensure that you/they do not break Tether.
(2) Speed Boost
Tether gives you and your target a 13-16% speed boost. This is useful for chasing enemy heroes or for running away from ganks. It can be cast on creeps as well.
If an enemy passes through Tether, it will be slowed and have its attack speed slowed by a large margin, for 0.75-2.25 seconds. This is a very rare benefit of Tether that is more coincidental than directly useful. Trying to set yourself up to to Tether through an enemy hero is more likely the get you killed in a bad position than actually earn you a kill. For the most part, I would ignore this function of Tether and be grateful when it had an effect in a teamfight.
(4) Pulling Effect
If Io Tethers to a target that is 700 or more units away (out of potential Tether range of 1800 units) then Io will be "pulled" to that target. This can help Io escape pressure from enemy heroes and improve his positioning.
This is especially effective when used to Tether up or down cliffs, where enemy heroes cannot directly follow.
A great example of this is when you are hooked by a Pudge. Unless the Pudge has a very quick hand, you should be able to Tether directly back to safety by targeting a nearby creep or teammate BEFORE Pudge can activate Dismember.
(5) Fight Initiation/"closing the distance"
Once Spirits has been leveled to max, the "pull effect" of Tether can be used to attack enemy heroes by approaching them faster than they can respond, especially in the laning phase. If you walk up to an enemy hero with your Spirits activate, most players will tend to back away from the spinning orbs, or perhaps attack you because they think you are a weak Io. By tethering to a friendly creep that the enemy hero is trying to farm (while you have Spirits active), you can pressure the enemy hero with physical attacks and Spirit damage (and possibly Urn damage, too). This is a great initiation route for getting kills in the earlier part of the game.
(6) Assisting your Teleport
Much like Storm Spirit's ultimate, Io can Teleport (using a TP scroll) during the "pull effect" movement of a recent Tether. First cast Tether on a far away creep or hero, and then immediately activate the TP scroll as Io is "pulling" towards his Tether target. This can increase the distance between you and an enemy hero with a stun or disruption, and can buy you valuable seconds for the TP cast to finish.
(7) Tree Removal
Io's Tether is useful for destroying large areas of trees. This is especially helpful in the early laning stages, where enemy support heroes will tend to harass carries from behind a treeline (for instance, Radiant safelane carry being harassed by Dire heroes from the Western treeline). By Tethering to a creep or hero from far enough away that the "pull effect" occurs, wherever Io stops/slows from the "pull effect" will have an area of trees destroyed around it. This is designed so Io does not Tether to save someone, but gets himself caught in the trees and unable to escape. By intentionally cancelling your Tether over a collection of trees, Io can maneuver himself to cut down trees faster than some Timbersaws.
This can be used to your advantage to destroy trees where you think enemy heroes will want to stand and harass you or your carry. The Radiant safelane Western treeline is one example. Another would be the Dire safelane trees that are just below their Tier 1 tower - removing these provides a greater avenues for harassing opponents and paths of initiation. Clearing trees in your own jungle to assist with neutral stacking is a viable option as well.
(8) Creep Block
This is a minor use of Tether, but one that I don't see performed very often. In the first 30 seconds of the game, players should be attempting to body-block the first creep wave. If Io makes a mistake in the first few seconds and lets a creep slip past, he is able to Tether ahead to his lane partner in order reposition himself ahead of that creep and have a 2nd chance to block effectively.
Spirits is a vastly underestimated spell. At Spirits Lv 4 (which you should have at Io Level 7), the spell provides 500 magic damage (5 orbs x 100 damage each) which is INCREDIBLY STRONG for a Lv 7 support hero. No hero in the game can match that damage output compared with such a short cooldown (14 seconds).
The orbs can be expanded and contracted, and the range of these orbs is amazing for netting Io kills that other heroes do not have the range to finish themselves.
There is very rudimentary advice I can give about getting better with Spirits expansion/contraction. Practice makes perfect. Practice practice practice.
(1) If you are chasing an enemy, EXPAND orbs.
(2) If you are about to be charged/stunned/dueled, CONTRACT orbs.
(3) Rhythmically switching between Expand and Contract essentially keep the Orbs from moving, and might be easier than trying to double-tap either command to lock the spin in place.
(4) Your range is better than their range.
(5) Aim for groups of heroes.
These orbs also have a minor AOE component, which means that when enemy heroes are grouped up, hitting one of them with orbs will damage multiple heroes. So not only can Io throw out 500 magic damage in a very short period of time, but he actually cause MORE than 500 magic damage by hitting heroes who are close together. Keep an eye out for this setup.
(3) Overlap Theory <-- This is f*cking important
"Overlap theory" is the idea that the floating orbs of Spirits last for 19 seconds, but the cooldown for the spell (at lv 4) is only 14 seconds. There is a 5 second overlap window whereby Spirits is active, but can also be immediately re-cast as a new spell.
This allows Io to engage in a fight whereby he already has Spirits active, can use those Spirits to cause 500 magic damage to a target, and then IMMEDIATELY cast Spirits again, causing ANOTHER 500 MAGIC DAMAGE to a target. This series of events can take place over several seconds and is CRUCIAL to Io getting kills and rapidly increasing his DPS in fights. 1000 magic damage is greater than a LEVEL 18 LINA ULTIMATE.
You're a lv 7 Io.
Let that sink in for a second.
If you activate Spirits early enough before a fight occurs, you can cause 1000 magic damage with Spirits alone. Not to mention your physical attacks (with or without Overcharge boost) and pure damage from Urn of Shadows. Combined with the Initation/"closing the distance" concept as described in How to Use Tether, this makes Io a f*cking deadly hero.
My item build is specifically designed to support this use of Spirits, because Soul Ring supplements the mana cost of constantly reactivating this spell.
(4) Shield Popping
If you have Spirits activated, and then proceed to cast another Spirits spell in the 5 second "overlap window", all previous Spirit orbs will explode to make way for the new 5 orbs from the 2nd cast. These disappearing orbs still do full damage upon explosion, and this means that by contracting your orbs as close to Io as possible, Io can act as a small suicide bomber with 500 magic damage worth of orbs surrounding him (and a further 500 about to spawn from the 2nd cast).
This can be used in 2 ways. The first is farming. Io can destroy creep waves or neutral camps by contracting his Spirit orbs and then "popping" his orb shield by activating a new Spirits spell, causing 500 magic damage in a small aoe around Io. This will clear an entire creep wave in one button push AND create a new 5 orbs that have a fresh cooldown.
The second use of this is in combat. A great example of this concept is Io vs Sven. If Io has fully-contracted orbs and Sven stuns Io and approaches to initiate a fight, Io can pop his orb shield as soon as the stun wears off. This provides a rather shocking 500 magic damage to an opponent who until 0.1 seconds ago had the advantage in this fight, and FURTHER PROVIDES a second wave of orbs that are immediately spawning and harassing Sven further.
It's not advisable to build your entire Io gameplay around this concept, because being close enough to enemy heroes to "shield pop" them puts Io in bad position. It is, however, the primary way Io farms waves/camps, and CAN be used when needed in teamfight situations.
(5) Speed of Expansion/Contraction
The speed at which Spirit orbs expand and contract is relatively close to Io's walk speed. This is an estimation, because Io's movement speed will change throughout the game as he buys new items. However, this can be used to confuse enemy heroes and improve your initiation chances.
Start by activating Spirits and expanding the orbs. If you were to approach an enemy hero right now, he would see your spinning Orbs before he saw you, and he would know "Io is approaching me, I should.... retreat/fight/cry/etc." If, however, you approach the enemy hero AND contract your orbs at the same time, the speed of your walking VS the speed of contracting orbs provides a net movement of 0. This means the enemy hero sees spinning orbs, but does not realize you are approaching him. To him, Io seems to be in one place and not moving, because while the spinning orbs are visible, they are not getting any closer. Once Io comes into view of the enemy hero, it is already too late for him. Now, you can expand your orbs back out again, easily clearing the distance it would take for them to smash into the enemy hero.
Spirits can provide vision to Io in multiple ways. First off, if a Spirit hits a enemy hero, that hero is visible for several seconds. NO ONE SEEMS TO REALIZE THIS. Often times heroes who have been hit by Orbs while hiding in the trees will stay there, not knowing that the Orbs have provided vision of their location to your teammates. This is especially important against Monkey King, the newest hero in 7.00. While Monkey King is using Tree Dance, any damage from Spirits will not only provide his location to your team and make him targetable for other spells, but it also resets Monkey King's cooldown to jump to a different tree, immobilizing him in one spot and allowing for him to countered.
Second off, Spirits will hit invisible players. This can serve as a warning sign that invisible players are approaching your position to gank. Often, expanding/contracting Orbs and attempting to mimic the pathing of an invs hero provides several Orb collisions, essentially painting a path that this invs hero is taking. This can be used to track the movement of an invs player, as well as potentially getting the kill on a hero you can't even see.
Third off, Spirits will NOT hit illusions. Seeing Orbs fly through an enemy hero is 100% guarantee that the hero in question is fake.
Overcharge is the most misused spell on Io. This section of the guide is a logical exploration of when and how it is viable to use Overcharge.
Overcharge drains 4.5% of your current HP and MP per second in order to provide you AND your Tether target with increased Attack Speed (40-70) and Damage Reduction (5-20%).
This is a relatively straightfoward spell that is VERY EASY TO F*CK UP.
The easiest advice I can give about Overcharge is DO NOT TO LEAVE IT ON. You will kill yourself or render yourself useless without mana if you forget to de-active this spell. If you are chasing an enemy hero and not attacking, TURN OFF OVERCHARGE. You won't gain any DPS if you're not actually attacking. If you expect that you will be stunned or silenced, TURN OFF OVERCHARGE. Any damage that Overcharge will block from the incoming stun and subsequent damage will most likely be negated by the damage Overcharge does to you during the stun/silence.
There are several qualities to Overcharge that are overlooked by the vast majority of Dota 2 players. Firstly, Overcharge will eventually stabilize at point where your current HP is low enough that a loss of 4.5% per second is LESS than your HP regen. At this point, the HP you lose from Overcharge is less than or equal to the HP regen you gain naturally per second, and when you Overcharge, you will not lose or gain net HP. This "baseline" can be raised by increasing your HP regen.
Secondly, the higher your CURRENT HP is, the more damage you will take from Overcharge per second. This is relatively straightforward - 4.5% of 2000 is more then 4.5% of 100. Because Overcharge takes a PORTION of your HP, no matter how much is available, the less you have, the less it will take, until you reach your baseline.
Because the cost of using Overcharge is so high (4.5%/sec of your HP/MP is no joke), an important question to ask is: When should you be overcharging? When should you not be overcharging?
Overcharge has 2 functions, one for Attacking (attack speed) and one for Defense (damage reduction). In order to answer the question of when best to Overcharge, we must compare each of these states (Attack and Defense) against the two types of Tether states, UnTethered (Solo) and Tethered.
Attack * Solo --> Good
If you're alone, you can use Overcharge to increase your own attack speed. This can help Io get kills by increasing his DPS in conjunction with his other skills. It is dangerous, because you are paying HP and MP to increase how rapidly you take away another player's HP, so use with care. This is also a good tactic for pushing towers and rax. Just make sure not to lower your HP too significantly in case enemy heroes are nearby, and to heal if you can.
Attack * Tethered --> DOUBLE GOOD
This is the single BEST way to use Overcharge. You are paying the same cost as in Attack * Solo, but you are getting double the net attack speed (once for you, and once for your Tether target). This greatly increases DPS output from you and your teammate and can net your team important kills and pushed towers.
Defense * Solo --> BAD. SUPER BAD. REALLY REALLY F*CKING BAD.
This is the WORST way to use Overcharge. The logic here is that you are attempting to block incoming damage onto yourself by activating Overcharge. However, often times the damage reduced by Overcharge is not worth the HP loss that Overcharge inflicts. The example below illustrates this concept.
I have built an Excel Spreadsheet that calculates the damage Overcharge deals to Io per second. Lets say Io has 1000 HP, and an HP regen of 8 HP/sec. Lets say a Lina is chasing the Io and wants to cast a Lv 2 Ultimate (650 magic damage, 487.5 HP points after 25% magic resistance). Io begins Overcharging as he runs away, expecting to be hit with spells. He is able to make it for 4 seconds before Lina ultimates and hits him with Overcharge activated.
After 4 seconds, Io has Overcharged himself from 1000 HP to 864 HP. Once the Lina ultimate hits Io, Overcharge removes 20% of the 487.5, and the Lina ultimate hits for 390 HP points worth of damage. Io immediately turns off Overcharge, and sits at 474 HP.
If Io had NEVER OVERCHARGED AT ALL, the Lina ultimate would have hit for 487.5 HP points worth of damage, and Io would be sitting at 512.5 HP.
It's clear from this example that even a brief overestimation in Overcharge can have a net negative effect on Io's survivability. Even in this example, the time it takes for the Lina ultimate to make contact, and the time it takes for Io to turn off the Overcharge, is set to 0 seconds, when in reality it would be another additional second of cast animation from Lina before Overcharge could be turned off, dealing even more damage to Io. Even if Io Overcharged for 3 seconds instead of 4, he still manages to have less HP than if he hadn't Overcharged. And in this scenario, Io had not gained the 32 HP he would normally gain (8 HP/sec * 4 seconds) if his maximum HP was above 1000.
There are exceptions to this rule. Turning on Overcharge the moment before a Sniper Ultimate hits you, and then immediately turning it off again, will block 20% of Sniper's damage while hurting you relatively little. The problem with examples like this is that very few spells are so obvious as to be able to predict the exact moment they will hit. Overcharging for even several seconds on either side of the incoming spell would negate the damage blocked by Overcharge in the first place.
Defense * Tethered --> Good
Overcharge can be used to block incoming damage on a Tethered teammate. This is a valid way of using Overcharge because it presumes Io is not being focused by enemy damage. Io is sacrificing his own HP/MP, but it's done in order to ensure another hero's HP does not drop below zero. Overcharge also comes into play as a HP-lowering spell, in order to ensure that Io's self-healing items will have maximum effect on the Tethered party.
Your Overcharge "baseline" is defined by the following mathematical relationship: 1 HP regen = 22.222222 HP. If you have 8 HP/sec, your baseline is 177.7 HP, meaning that if you activate Overcharge when your HP is at 177.7, you will not gain nor lose HP. If you Overcharged very close to your baseline, lets say 190 HP, you would only lose a very small fraction per second (1 HP or less, according to my numbers). If you Overcharged at 150 HP, you would gain net HP, despite the damage from Overcharge.
Your baseline varies according to your HP regen. 8 HP/sec has a baseline of 177.7 HP. 10 HP/sec has a baseline of 222.2 HP. 20 HP/sec has a baseline of 444.4 HP. Etc etc etc.
Another exception to the Defense * Solo Overcharge rule is when your hero is close to their baseline. Overcharging in this scenario deals very little damage to Io, at which point the 20% damage block becomes viable and useful - it might be the thing that keeps you alive. Lets present another example to illustrate this principle.
Io sits at 177.7 HP with 8 HP regen/sec, and therefore 177.7 is his baseline. In one reality, Io does not overcharge. Over 4 seconds, he gains 32 HP (8 HP/sec * 4 sec), moving to 209.7. After the 4 seconds, he is hit with a spell that deals 210 damage, and dies. In the second reality, Io overcharges for 4 seconds. He does not gain or lose any HP, and is still at 177.7 at the end of the 4 seconds. He is then also hit with a 210 damage spell, but now survives, blocking 20% of the 210 (210*.8 = 168) and taking 168 damage. He survives with 9.7 HP remaining.
So, in summary:
(1) Overcharge to increase your damage output
(2) Overcharge to increase your + another's damage output
(3) Overcharge to block damage on another hero and to ensure your healing is effective
(4) DO NOT Overcharge to block damage on yourself, UNLESS your HP is close to your baseline
Double-tapping the Relocate button ("R" for some players, "4" for others) should activate Relocate and teleport you back to your base. If this does not work for you, you can change the "double-tap an item/spell to activate it on yourself" option in the Settings menu.
Relocate teleports Io and a Tethered target to anywhere on the map for 12 seconds. After 12 seconds, Io and anyone he is Tethered to will be Returned to their original position.
(1) Escape or Save a Teammate
Relocate can be used to escape death by Relocating back to your base. This is effective because it negates the enemy team's pressure on you and in the process can waste valuable cooldowns and put enemy heroes out of position. Being back in the base refreshes Io's HP and MP, allows him to buy valuable items (especially if you think, on the Return, you will most likely be killed), and buys time for other teammates to move to the fight and engage with the enemy.
This principle is the same for when you are Tethered to another teammate. If someone is being Duel by an Legion Commander, or Dismember by a Pudge, or simply has low HP, you can Relocate them to safety. My advice is to activate Relocate FIRST, and THEN Tether to your intended target. Overcharging is also a good idea, to prevent the target from dying before Relocate activates.
You will have to make a judgement call about the Return, and whether or not it is a good idea to bring back the person you saved. If 5 enemy heroes are waiting for your Return, it might be best to leave the hero you saved and accept your death. 2 dead heroes is always worse than 1.
There are several common locations for Relocate. The first is back to base, where the healing and item purchasing can occur. This is where 98% of my save/escape-based Relocates are headed.
The second Relocate location is just outside of a teamfight. If a teammate is disabled by a spell, such as Batrider Flaming Lasso, teleporting that teammate all the way back to your base for 12 seconds removes two allied heroes from the teamfight (You + Teammate), which can weaken the position of your other teammates and could potentially lose you the teamfight. Instead, you can Relocate with that hero only several hundred units away - enough to break the disable spell, but not so far that they cannot participate in the teamfight. This saves your teammate AND stops the teamfight from becoming lopsided in favor of the enemy.
The third and least common use of Relocate takes a different approach. Rather than fighting with your team and Relocating to safety (only to Return back to the fight, which could be very dangerous) some professional Io players will opt to use a Teleport Scroll back to base, and then Relocate BACK to the fight. This provides the benefit of being able to Tether another teammate to safety upon your Return, while also increasing Io's survivability by ensuring he has 100% HP/MP. However, if the fight lasts longer than 12 seconds, Io is unable to teleport back to help further (as both Relocate and TP scroll will be on cooldown).
Relocate can be used to gank enemy heroes anywhere on the map. This is best performed when Tethering to another hero, to increase the DPS you can output in only 12 seconds.
When Io Relocates to a location, there is a "swirl" on the ground at the target location that is visible to enemy players. As a result, it is important to hide this swirl. The best way to do this is to Relocate into some trees that are near your ganking target. The trees will break when Relocate activates, so you do not have to worry about being stuck in the trees, and the enemy hero will have no visual clue that you are coming to gank. A riskier option is to Relocate DIRECTLY ON TOP of the enemy hero, so that his character model covers the swirl. If the hero moves, however, he will most likely see the swirl and register that an Io + Teammate is incoming, so this is best performed on stationary heroes.
(3) Dive/Killing Runners
Relocate can be used to catch low-HP enemy heroes that are running back through a lane towards their base. This will require some timing on the part of the Io, but the range of Spirits allows Io to deal high damage to far-away heroes, while Relocate ensures you will be Returned to your original position, no matter how deep you have to dive.
This USED TO BE viable for diving into enemy bases, by cutting off heroes who are running for their bases' high ground. HOWEVER - after the 7.00 patch and introduction of multiple fountains around the base, diving into enemy bases has become incredibly risky and is not advisable to even very high-skill Io players. Enemy heroes can now heal themselves rapidly without needing to stand in their bases' high ground, and can reverse onto Io aggressively.
(4) Pushing (aka Rat Dota)
Relocate can be used to push towers and rax, as long as there is no backdoor protection. The 12 second Return ensures that no matter how dangerous or risky the positioning is, Io + Tether buddy will always be returned to safety. Bringing a Tethered hero is required for maximum DPS, and choosing the top-damage hero on your team ( Tiny with Aghs is a great choice, or any hero with Desolator) will ensure for fast pushing.
Backdoor tower/rax regeneration is still an issue, but if the tower/rax has low enough HP, you should be able to finish it off before the Relocate is over.
This Relocating tactic forces the enemy players to remain close to base to defend against potential Relocates, and is a valuable method for controlling enemy movement in the endgame.
(5) Defending Towers
Io can use Relocate, if needed, to engage creeps that are hitting towers. While it is not the best use of the spell, the 12 seconds allows Io to eliminate one, if not two creep waves that are pressuring a tower that no one is defending.
(6) Changing Tether Targets Mid-Relocate
When Io Tethers to any target, the Tether lasts for 12 seconds, and has a cooldown of 12 seconds. HOWEVER - when Io Relocates, this refreshes his Tether, BUT NOT THE COOLDOWN. This means you can potentially have a 24-second-long Tether, by Tethering for almost 12 seconds and then activating Relocate before Tether expires.
It also means that if you Tether a target for several seconds, and then Relocate to a new area, you can Break your Tether and re-Tether a new target to bring with you on your Return. Because the cooldown of Tether is not refreshed upon Relocate use, this allows you to bring Hero A into a teamfight, then re-Tether to Hero B and bring him to safety.
(7) Return can be CANCELLED?!
The Return portion of Relocate is one of the strongest spells in the game. It cannot be overpowered by any stun, root, disable, or item (such as Eul's Scepter of Divinity). There are, however, some ways in which Io will NOT be Returned to his original location.
The first is through Pudge Meat Hook. If Pudge hooks Io, and Io is being dragged towards Pudge as the Return activates, Io will Return to his original position before being teleported back to Pudge. Something about the way Hook works with heroes and positioning means that Io will not be Returned. This can be used POSITIVELY, such as a teammate Pudge saving you from a bad Return, or NEGATIVELY, by a enemy Pudge preventing you from escaping.
The second way to cancel Return is through other "returning" spells. Kunkka X Marks the Spot is a classic example, whereby Kunkka can X the Io, wait for him to Return, and then activate the X spell to bring Io back. Keeper of the Light Recall is another example of this, where KotL can start the Recall spell before Io has Returned, and time it so that the Recall spell will activate very soon after Io Returns. A well-timed Underlord Dark Rift can accomplish the same thing.
The third way to cancel Return is via a Teleport Scroll, and is without a doubt the MOST DIFFICULT Return cancel to perform. It operates on the idea that if the Teleport channeling spell completes itself at the exact moment that Io Returns, the Teleport will override the Return, and the Io will move to the Teleport location and not the Return location.
My best advice to accomplish a TP scroll Return-Cancel is to activate the scroll just before the countdown timer for Return hits "3". There are several microseconds of time between clicking the intended location of the Teleport Scroll and 3-second channeling spell actually beginning, and this must be factored in when trying to execute this move. The window for activating the TP scroll successfully is INSANELY small (several frames, I would imagine), and you will fail more than 9 times out of 10. Activate the TP too early, and the Relocate will cancel the channeling spell. Active the TP too late, and Io will successfully TP... and then Return. Practice makes perfect.
(8) Relocate and Glimmer Cape - Two Best Friends
Glimmer Cape is your best friend, especially when it comes to Relocate. While Glimmer Cape may help you activate the Relocate without being stunned (although you will break Glimmer's invisibility when you start the Relocate spell), it is mainly used on the Return portion, where one or several enemies may be waiting to kill you.
Glimmer Cape provides 5 seconds of invisibility after a 0.6 second pause. Glimmer can be activated 1 second before you Return, and will render you invisible for when you Return to your original position. This will buy you valuable seconds to move away from the Return location and potentially Tether away to safety. Enemy heroes will be staring at the "swirl" that is left by your Relocate, and will simply see the swirl disappear without any presence of Io. This confusion also plays to your advantage in moving away from the area.
Another use of Glimmer Cape is to disassemble the item (which can be done at any time) into a Shadow Amulet, which allows Io to remain permanently invisible as long as he does not move. If you are Returning to a particularly bad situation where the 5 seconds of Glimmer Cape would not be enough to save your life, you can split the Glimmer Cape into Shadow Amulet and activate that instead, which renders Io invisible but immobile. As with Glimmer Cape use, the enemy team will simply see a swirl disappear without a trace of Io, and should eventually leave the area to go do something else. The only way you will be killed in this situation is if an Axe uses Berserker's Call to force you to attack, Zeus uses Lightning Bolt, Lone Druid uses Savage Roar, or if someone uses Dust/Sentry Wards on a hunch that you are invisible. Other than in these circumstances, this technique provides a MUCH higher chance of Io's survival, and also really impresses your teammates.
In this section I defend my logic behind my Talent choices.
Lv 10 --> +6 Armor or +10% Magic Resistance
This selection depends greatly upon your intended items later in the game. I always play Io with Glimmer Cape, which offers 15% Magic Resistance with an activation that applies another 45% Magic Resistance to yourself or another target. As a result, I feel my Magic Resistance is strong enough (possibly supplemented by a Pipe of Insight later in the game) and I often select +6 Armor at lv 10. However, if I was playing a Carry build that had armor built in (via an Armlet of Mordiggan, for instance), then I would select Magic Resistance.
Using this build, Io at Lv 9 has 2.4 natural armor + 3 armor from Tranquil Boots, totaling 5.4 armor = 24.5% physical damage block. At Lv 10 with the +6 Armor talent, Io has (2.6 + 3 + 6) = 11.6 armor = 41.0% physical damage block, an increase of 16.5%!
On the other hand, the +10% Magic Resistance talent buff is calculated AGAINST the 25% natural magic resistance all heroes have, in the following formula 1-((1-0.25)*(1-0.10)) = 32.5%, meaning the +10 Magic Resistance talent only nets you +7.5% magic resistance!!!
The answer is in the math.
Lv 15 --> +10 Mana Regen or +10 Strength
+10 Mana Regen. It's not even a competition. It's not even a f*cking question. This is the most blatant choice of all the talents Io has, and let me explain why.
+10 Mana Regen is insane. That Talent will fix your mana regen for the entire game. NO FURTHER MANA REGEN ITEMS REQUIRED. No Arcane Boots, no Soul Ring, no Guardian Greaves, no Eul's Scepter of Divinity, nothing else is required. This is single-handedly the biggest buff to Io in the 7.00 Patch. Overcharge without fear of losing all your mana. Spam Spirits to your heart's content. I really cannot overstate how insanely important this talent is.
Another way to view this is through cost. How much gold would it cost to buy items that would offer you the same effect as the talent? Well, +10 Strength is a Ogre Club, which is 1000 gold. +10 Mana Regen....is not even fathomable. A Eul's Scepter that cost almost 3000 gold would not provide +10 Mana Regen.
Using my items as described in this build, my MP regen rises from ~3 MP/sec to ~13 MP/sec with this talent, allowing me to sell Soul Ring and open a new item slot in my inventory.
Pick this talent. Anyone who says otherwise is a fool.
Lv 20 --> +20 HP Regen or +120 Gold/min
My logic on this talent selection comes from the #1 Io player in the world, Ziqi. Before talking to him, I would always pick +20 HP Regen - I figured that whatever gold I would gather from the +120 GPM talent would just go towards healing items anyway. However, Ziqi set me straight.
"You cannot win the game with +20 HP regen. You can win with Heart of Tarrasque, and for that you need gold"
Ziqi was being very specific, but his point was clear. The gold gathered from this talent allows you to purchase end-game Io items, which can dramatically alter the effectiveness of the hero in the late game much more so than +20 HP Regen. Heart of Tarrasque is a great example, which can single-handedly win games by keeping major carries alive through critical teamfights. Other big endgame Io items, such as Black King Bar, Octarine Core, Boots of Travel, or even Desolator are all expensive and require gold that Io does not have the time (or the priority) to farm.
The +120 GPM talent helps supplement Io's gold intake and allows him to transition into the endgame far better and with more versatility than the +20 HP regen talent.
Lv 25 --> +150 Spirits Damage or -50 Seconds Respawn
The +150 Spirits Damage is an incredibly strong boost to your Spirits spell, which by Lv 25 has become less-than-lethal and more like mildly-annoying for the enemy. If you are skilled with the movement of Io's Spirits, this talent is a DEADLY choice. The damage of a full Spirits cast moves from 500 magic damage (5 orbs x 100 damage) to 1250 magic damage (5 orbs x 250 damage), which as explained in the Skills portion of this guide, can be effectively stacked to 2500 Magic Damage.
Let me repeat that. 2500 Magic Damage. I have played games with Io where I do not score any kills from level 17 to 25, and suddenly at 25 get another 4-5 kills with +150 Spirits talent.
-50 Sec Respawn has its uses, but I feel by this point in the game, it doesn't make sense to get. -50 Sec Respawn would provide you a quick respawn to get back out into the field and help support that all-important carry. But if the carry has died, and Io respawns early, there's not much you can do to stop a push towards your base. If you are constantly dying at Lv 25 while your carry stays alive, then maybe the problem is in your items, not in your talents.
The potential damage output from Spirits outperforms the potential maximized support of -50 Sec Respawn.
(For what it's worth, Ziqi chooses -50 Sec Respawn, but N-R-C swears by +150 Spirits)
Thank you so much to the Dotafire community for putting this guide on the front page, as the #1 spot on the "Top Dota 2 Guides (Last 30 Days)" charts from 2-19-17 to 3-20-17.
I will try to update this guide with more short videos to help explain the moves I am describing.
I hope that by reading through this guide (or just the portions you were interested in) that you have gained a deeper understanding of Io strategy, and that I have effectively defended my reasoning behind the decisions I made.
I plan to use this guide as my own personal record of successful Io ideas, and I will be updating this guide as I find new combos and item combinations that are more effective than the last. So feel free to check back in a few months and see what I've come up with.
Newest Update -- Lotus Orb can dispel things I didn't even know were dispellable (See New "Situational Items" Section Update)
A big thank you to everyone who has said nice things about this guide, subscribed to my channel, or sent positive feedback. Hopefully you guys can be pulling moves like this soon -
And an extra special thank you to everyone who gave me advice or guidance about Io - I couldn't have done it without you.