Viper specializes in pinning down single targets from a distance, while dealing moderate damage. His Poison Attack allows him to consistently slow someone down, and he can fire a heavily concentrated Viper Strike toxin to nearly stop someone in their tracks, and deal good damage over time. This allows him to be more aggressive as he can go in and keep targets from escaping. To aid with leading a charge, he's developed Corrosive Skin that offers resistances, returns minor poison and slows the attacker. While most of Viper's damage is dealt over time with poisons, he has a passive Nethertoxin which allows him to deal additional damage to weaker units.
A malicious Drake tamed by the Lich King himself, Viper is a fierce, acid-spitting beast whose speed and agility surprises the most hardened of warriors. Cursing himself into a maddened rage, Viper charges into battle without regard of his own safety. His salivary glands produce stinging poison that causes enemies to writhe in pain, severely damaging their nerves. Be careful when facing this powerful monster...its dark silhouette may be the last thing you will ever see.
Justification: For last hitting and a slight damage boost for harassing. The bonus damage comes in handy to score last hits and getting farmed up quicker and the tangos are for healing purposes.
Justification: The two slippers are built up into two Wraith Bands, giving a +18 boost to damage, as well as a slight increase in HP. The main question here is whether to get Power Treads or Phase Boots. Treads give Viper the much needed Agi/Str boost, both for attacking/survivability, as well as an increase in attack speed. The only bad thing about this option is that Viper really needs the extra movement speed. Phase boots, on the other hand, gives a 16% extra speed bonus through Phase and +24 damage. However, this option sacrifices the stat bonus.
It really depends on the situation you are in - are you having difficulties laning/constantly being ganked? Go for Treads if this is the situation you are in. If you have not much of a problem, and you want to farm better/kill faster/chase faster, go for Phase Boots.
Finally, the TP scroll is Viper's escape mechanism.
Justification: Being a carry, the damage and agility boost is much required. Shadow Blade gives a +38 damage boost, +10 attack speed and Wind Walk. This is VERY important as Wind Walk becomes Viper's escape mechanism, as well as for ganking. The 150 backstab damage is very helpful in picking off low HP, solo heroes.
Other than Shadow Blade, Manta Style is also a viable option due to the extra Agi and movement speed. Once Viper gets his core, his movement speed will not be that slow anymore. Mirror Image can also buy time for Viper to escape from ganks. Either one of these two items are essential in a carry Viper's core.
Monkey King Bar is also a core item as it provides Viper with a great damage boost, and it allows him to counter his weakness, TP Scrolls.
An underrated and commonly neglected item on Viper would be Aghanim's Scepter. This item is great for Viper before the 20 minute mark, seeing as it increases his mana pool and can be spammed, maximising Viper's early/mid-game dominance by being able to snipe down single targets. However, do take note that this item should either be rushed first as a carry, or completely skipped if you decide to go for the DPS/survivability build. This is because the boost from Aghanim's Scepter late game is insignificant if both sides are evenly matched.
Late game items:
Justification: That's all. The huge Agility boost and evasion makes Butterfly the ultimate Agility hero carry weapon. Viper will morph into a fearsome carry with this item late game.
Justification: The luxury items depends on the situation as well. Get a Heart of Tarrasque for survivability or an Orchid Malevolence to silence spellcasters/deal extra damage. The Critical Strike from Daedalus multiplies your DPS by 1.375x, and +88 damage is a significant boost to your DPS as well.
Justification: The two gauntlets give a +6 boost to Strength, or 114 HP. These gauntlets can be later upgraded to Bracers or an Urn of Shadows. The Stout Shield provides some early game damage block, so as to increase survivability. Likewise, the Stout Shield is part of the core item, Vanguard.
Justification: This is a build up from the two gauntlets that were purchased at the start of the game. In addition to the two bracers, Viper can opt to have Str treads to further boost his HP. The total HP addition from these items is 380, which is quite a fair bit. It shouldn't be hard to get Viper's HP above 1000 with these items.
Justification: Two HP boosting items to make Viper tankier. Once Viper is able to get these two items, his HP should be around the 3000 HP mark. Yes, very fat indeed.
Late game items:
Justification: Butterfly has evasion which makes Viper even tankier. The main reason, however, of getting one of two of the above items is so that Viper does not lack in damage. Butterfly is the preferred choice, adding to Agi and providing evasion, but Monkey King Bar is not too bad as well, given that it has ministuns. I would say that the components of Monkey King Bar are slightly easier to farm than Butterfly. This is up to player preference.
Justification: Even though Linken's Sphere is relatively cheaper as compared to the late game items, I classify it under luxury items. The main reason being that Viper will already have sufficient HP to resist against nukes and will have a high chance of getting away from ganks alive. Linken's Sphere will add on to the regeneration rates and help to negate spells. A good add on to Viper's existing core. There is nothing much that can be added on to Viper's late game item build, other than another Heart.
Viper has an attack range of 575, of which Poison Attack adds a further 25 on top of it, making that range 600.
Also, since Poison Attack is a spell, enemy creeps will not attack you when you harass the enemy. As such, try to move as far outward as possible to harass the enemy, ensuring that he gets nowhere near your creeps and cannot farm at all.
There will be scenarios where you are being chased back towards your base. If the enemy does not chase you until you die, they will inevitably turn around. You must always be prepared for this moment when they disengage and turn around. When they turn around, immediately land 2 to 3 Poison Attacks on them by orbwalking them/cancelling animation. This will reduce the gap in terms of damage exchanged, and make them regret ever chasing you.
Question - When do you harass?
Answer - Whenever you can. Best if the enemy you are laning with is a melee hero. At level 3 of Poison Attack, you can easily land 3 Poison Attacks on him before he reaches you. Everytime he attempts to last hit, Poison Attack him. If you want to last hit, chase him back by Poison Attacking him. Viper can be a frustrating hero to lane against early game due to the constant damage per second you take.
Question - What if the enemy I am laning with is a high damage nuker? (e.g. Lina/Tinker)
Answer - Continue to harass him as much as possible, though do your best to stay safe. I'd recommend to get more healing consumables to minimise damage done to you. In the case that you are badly injured, ALWAYS use the courier to ferry a salve/clarity to you rather than walk back all the way.
Don't let those nukers have free farm early game. Their skills are extremely painful and by the time you return, they may have skilled another level of their nukes which will give you a harder time farming. Besides, you save the time travelling back to the fountain and 135 gold to buy the teleport scroll.
Question - What if the enemy I am laning with has a high DPS/range as well? (e.g. Shadowfiend/Drow Ranger)
Answer - Similarly, continue to harass him as much as possible. This is especially important against high DPS heroes such as Shadowfiend and Drow Ranger as they can carry their team as well. It may be painful, so stock up on healing consumables as well. You may want to get a Ring of Regeneration to help cope with the damage if necessary. Don't let them have a moment of free farm; you will regret it later on in the game.
Question - What if the enemy I am laning with can heal himself constantly? (e.g. Shadow Priest/Necrolyte)
Answer - Go aggresive. Charge at him full force and keep orbwalking him, or spamming your Poison Attack. In early game, their healing spells have restrictions to them. By constantly harassing them, their HP should constantly hover at the 50% or less mark. Eventually, he'll run out of mana and will be forced to retreat, allowing you to have some farming or even push a little.
Question - What if the enemy I am laning with is a high HP tank/strong attacker? (e.g. Skeleton King/Slithereen Guard/Doom Bringer/Spiritbreaker)
Answer - Play defensive. With their stuns and a couple of hits, you can easily take more than 50% of your HP as damage. Instead, try to stay as close to your creeps as possible, so they will attack the enemy if he attacks you. Abuse your range and stay as far away from him as possible while harassing him with Poison Attack. Though the damage may not be too much, it will keep him back for some time, preventing him from getting the precious farm. Likewise, you can also get healing consumables or go for a Vanguard if you like.
In order to be a good Viper carry, you need to have good farming skills. One must know the mechanics of last hitting and farming in DotA.
Maintaining creep equilibrium helps alot in your farm. The lanes in DotA have an innate creep equilibrium; however, the slightest thing can change it. There are several ways to keep the creep equilibrium in your favour: Last hitting, creep blocking and creep pulling.
Last hitting is basically when you land the killing blow on a creep, getting the gold from it. When you play Viper, here are the things that you need to know so that you can farm effectively:
[+] You need the health bars of the creeps to be on. This helps alot in estimating when to land the last blow.
[+] You need to know how much damage you do as a percentage of the creep's HP.
[+] You need to know how to cancel animation/time when to let your projectile go.
[+] You need to be able to predict denies from your opponent so you can last hit before/after his projectile hits the creep.
[+] You need good harassing to keep him away from the creeps while you farm.
[+] You need to know how to draw aggro so that you can farm (in some cases).
Creep blocking in mainly used in the beginning of the game to stall your own creeps from moving from the spawning point to the connecting point at the river. By stalling the creeps you move them closer to your side of the map, making you safer from ganks or attacks. Besides, you get an advantage over the enemy hero and creeps. When effectively executed, this allows you to attack your opponents without fear of being attacked. You now have the fog of war and evasion on your side. Everytime your enemy tries to attack you, he has a good chance of missing.
In order to block creeps, you should stand below the slope in front of the barracks.
To stall them you can keep walking directly in front of them, or you can also press "Stop" while continuously moving in front of them. This will cause your hero to stop for a split second, and the creeps behind you will be blocked and will fumble, trying to get around you. You should be pressing the Stop button as much as possible, without letting the creeps pass you.
Why is creep blocking good? If the enemy is ranged, he misses a lot on attacks because of the up-slope miss chance. If the enemy is melee, he cannot attack you without risking being attacked by the tower/draw aggro and take damage from creeps. This is the value of creep blocking.
Creep pulling relies on the mechanics of creep aggro. When you give the command to attack an enemy hero, the enemy creeps will switch their target to you. Note that spells do not draw creep aggro.
As a ranged hero, you can use this technique against melee heroes. Draw the creeps to your tower to help clear waves faster. The disadvantage about this is that you will have to tank some damage, both from the creeps and possibly the enemy hero. Also, if you fail to pull it off, you will take damage for nothing.
Some mechanics regarding creep aggro:
[+] Creep aggro effect is 500 distance from your position.
[+] Creep aggro lasts 2 seconds.
[+] The location of the Hero does not matter; you can click a hero accross the map, but if there are creeps within 500 distance of you, you will aggro them.
[+] The aggro occurs the moment you click the attack command, rather than when you actually attack them.
[+] Giving the attack command while outside of 500 creep range causes the moment of aggro to be triggered when you actually attack (again, the condition that creeps within 500 range applies).
The most important thing when ganking is to maintain distance from the target and ascertaining the safety of your environment (e.g. No potential dangers such as other enemy heroes/within tower range). Be careful not to go into his radius of sight too early. Close in when you are ready. Viper can initiate with Viper Strike for the damage over time and slow before orbwalking him to death. If you are confident, you can choose not to use your ulti and save it for other situations later.
Viper Strike at level 3 deals 725 damage over the whole time of the spell (544 damage after 25% hero spell damage reduction and has a 30 second cooldown. You can use it in situations whereby:
[+] The enemy HP is low and he has the ability to escape with invisibility/blink. Even if he does escape, the damage from Viper Strike will kill the enemy.
[+] You are in a 1v1 battle. Viper Strike can be used to help in killing your target faster.
[+] You need a slow. The 80% slow from Viper Strike at level 3 will definitely allow your teammates to catch up to the enemy, killing him.
[+] Extremely good harassing and lane control - prevents enemy from farming while he gets farmed up.
[+] Strong early and mid game, can transition into a powerful carry at mid/late game.
[+] Can chase and kill easily due to the slow from Poison Attack.
[+] Very versatile, can play many roles in the game.
[+] Wide item pool - there is no sole item for Viper.
[+] He looks cool.
[-] Low base movement speed - hard to escape.
[-] Low base HP - easy to get killed in teamfights/ganks.
[-] No escape mechanism.
[-] Countered by a TP Scroll.
Good Allies :)
Prevents you from dying in ganks, can support you while laning and helps you escape safely.
Another escape mechanism for Viper on top of his build.
Basically any hero that can stun and prevent Viper's enemies from teleporting away while Viper is orbwalking him.
Due to Viper's generally low HP, nukes can kill Viper pretty quickly early and mid game.
These heroes make Viper's Poison Attack useless. By relying solely on his own DPS, Viper can potentially lose to other DPS heroes with a higher HP than his.
Fast chasers/Strong attackers:
These heroes can outrun Viper in the situation that Viper tries to escape from a gank or teamfight. As most of them are Strength heroes, they are pretty strong and have a good amount of HP, therefore being able to kill Viper in 1v1 situations easily early and mid game.
Mana burn makes Viper completely useless. Without his first skill, Viper can only rely on his normal attacks to kill (which won't be THAT painful or powerful early/mid game). If you're having troubles against mana burners, you can consider stocking up on a few clarities or perhaps a bottle.
Magic immunity renders Viper's Poison Attack useless. Similar to mana burn, Viper can only rely on his normal attacks to kill enemy heroes. Omniknight's Repel allows him to safely run away from Viper's orbwalking process, and Guardian Angel just prevents him from dying. Barathrum can cast Nether Strike on you as you are orbwalking him to change the tide of the battle.
First of all, I would like to give credit to gwho's Guide to Dodge Viper. It was a pretty good guide written there, and I based some sections off that guide.
Secondly, I would like to give credit to HonorGuard's Guide to Improving Yourself. That guide provided me with the information on farming effectively, which I integrated into this Viper guide.
Lastly, I would like to thank each and everyone of you who commented and helped in improving my guide. That would include you, dear reader.
I would like to mention that I spent more than 40 hours on this guide. I would love to improve this guide to my best ability to provide a good Viper guide for the DotA community.
You can always drop me a PM or a comment and I will do my best to reply you.
Thank you all for spending your time to read this guide. I sincerely appreciate it.