My name is Peppo_o'Paccio, I enjoy playing Dota 2 very much and I also like watching competitive Dota 2 games. I decided to make a guide for Wraith King because I think he's such an underrated Hero: he doesn't have many useful skills, but with the right items he can become literally immortal; I think he can keep up with other similar hard carries like Sven if given enough farm.
He is rarely picked in competitive games, but there are many reason to choose him between other "harder" carries which I'll explain in another chapter.
Wraith King's skill build is not difficult to learn, there is just one effective way to level up his skills: he is not either a ganker or a jungler, so you don't want to level up Mortal Strike (which also deals minimum extra damage early on) and Vampiric Aura early. In particular, the latter will just let you push the lane, which is a terrible mistake.
As you can see I wrote "Melee" between the cons: it isn't completely a downside but, especially on Wraith King who doesn't need any cleave item and almost never a shield, it's not so nice for unexperienced players. Of course there are many positive things about it (there are really few ranged Heroes that rely on DPS and attack speed while being strong carries) but a player that has never played WK should always remember its downsides so he can playing better. If you want a more in-depth explanation, take a look at this nice article by xCO2.
Wraith King is not one of these carries that can be played in any situation: in fact he needs a good trilane (or a good lane partner that gives you kills if you are playing in pubs) and a good amount of free farm. Also, he is really weak if compared to Sven: they do the same things, but Sven can do them almost always better until the game reaches the very late stages. The big upside, though, is that WK already has damage steroids and built-in regen for the laning phase: these leads to a more attack speed-oritented build since almost all STR carries lack agility points.
This can be defined as Wraith King's bread-and-butter skill for two main reasons: this is the only active spell he has and this gives him a lot of presence in the early ganks or teamfights. This skill damage scales terrificly and can kill enemies thanks to the damage over time it deals.
Remember that this skill not only stuns and damages the enemy, but even slows and deals damage over time: this is a thing that people usually forget and it's also why it is so feared in the early game.
Don't forget that it costs a lot of mana, and this is why you should level up your stats early. If you feel like your mana is always low pick one of the mana-regen items in the situational item section.
This skill is one of the best yet worst lifesteal abilities in the game, depending on the stage of the game. It gives a good amount of lifesteal to all units around you, wether they are creeps or Heroes.
In the early game, never level this up past level 1: a skill point on Vampiric Aura ensures you don't have to get any regen items (Ring of Health, Morbid Mask...) so that you can stay in lane for as long as possible; creep pulling (provided your support is a decent player and does it) should diminish the small pushing power it gives. Still, if you give to much lifesteal to your creeps they will push the lane and you will probably be ganked non-stop under the enemy tower.
On the contrary, while mid/late game shows your team's Heroes (including you) have the best lifesteal in the entire game: compared to Vladmir's Offering's lifesteal (16%) even just one skill point can make yours almost the same (15%) and works on ranged Heroes, too. Compared to Satanic's lifesteal (25%), your maxed-out Vampiric Aura will heal more (30%) and to all of your teammates.
Mortal Strike is the typical damage proc many Heroes have and that no one skills before level 7, when you should finally have damage-increasing items and good stats. If you put points into this instead of stats you would commit two mistakes: first you won't have the extra mana for Wraithfire Blast (even though it's a minimal amount, it's really useful); secondly you would deal very little extra damage and, eventually, miss some last hits.
If you are afraid you won't have skill points on this before the most important teamfights happen, remember that you are a hard carry: you shine in the late stages of the game, in which your level should be even higher than 13, when you max out this skill.
Lastly, remember that when levelling this up you won't improve the percentage of critical hits, but just the percentage of damage. You will always deal 1.5 critical strikes every 10 hits, so you should focus on attack speed and not only on heavy DPS. Also, you should know that this is not an orb effect so you can take, for example, a Mjollnir and proc both critical strikes and lightinings.
This ultimate is what makes Wraith King able to soak up a lot of damage and still be able to kill and dominate teamfights. This sounds like an impressive skill, but in fact it has two weaknesses: mana burn and cooldown.
While picking Wraith King you should always avoid Heroes who can burn your mana and set up your item build accordingly. If you are against and Anti-Mage (which you should always ban in competitive games if you're going to pick Wraith King) always buy a Soul Ring. If a Keeper of the Light keeps on leaking your mana buy an Eul's Scepter of Divinity and cyclone yourself (or him, if he hasn't activated his Mana Leak yet) or - simply - go for a quick BKB.
Lastly, you should have noticed that this ultimate slows the enemy movement speed if they are close to your tomb when you resurrect: this looks like it isn't that useful, but keep in mind that WK's main weakness is kiting and slows make it impossible.
Unlike the majority of Heroes, Wraith Kingneeds stats, they are vital for him. Without at least a stat point in the early game you won't be able to use your Wraithfire Blast more than twice and your Mortal Strikes will deal very little damage.
Previously, before WK was given more starting mana, people would pick two points of stats: now that Tranquil Boots have been reworked and the Vanguard isn't cost-efficient anymore, I think that getting a point of Vampiric Aura at level 4 is the best way to keep your laning phase in the right track, so you can get away with a single stat point.
This is the way Wraith King is played in competitive games if he takes a core position: unlike the "harder" carries, he already has built-in lifesteal and crits, so you can take advantage of his "item independence" and focus on the early game. The Blink Dagger is an absolute must, as WK's weaknesses is his low mobility; it also makes you become a feared initiator (if you Blink-stun and they focus you down, you'll Reincarnate anyways) and a perfect ganker, especially with a Smoke of Deceit. Wraith King is one of the very few carries with a stun, if you aren't planning to buy a Blink on him you could pick a different semi-carry (unless you need to go late game).
There isn't much to say about the starting items: as you'll be playing in a contested lane (or even in an aggressive one) a Stout Shield is always needed.
Two items for regeneration are just enough, but remember you couldn't survive without both even with your built-in lifesteal: buy a Tango and a Healing Salve.
Lastly, fill your empty slots with Iron Branches. Someone might argue WK needs Clarity potions for his mana, but I think that a Magic Stick from the side shop will do the job. Still, if you want to, drop a Branch for a Clarity.
Early game items
You don't need much else to be a presence in the mid-game and create space for your team: Power Treads are the boots of choice for the attack speed that synergizes well with both your passives, and Tread switching also helps a bit with mana issues.
Next, finish your Magic Wand: as said before, burst mana is almost mandatory (especially because it can save your life when you don't have enough mana to Reincarnate), and the extra HP you get from each activation comes in handy, too.
Lastly, purchase a Blink Dagger from the side shop: now you can stop farming and focus on roaming with your team trying to get kills, but going to the jungle in the downtime to get some farm is a good idea nonetheless. Just, remember you're a semi-carry: you aren't supposed to farm, you need to create space for your other carries.
This should be your main choice if you're having a good time: the attack speed from the Maelstrom is already good to speed up your farm, but the Hyperstone component just makes you much more fearful. Remember, the more attack speed you have, the more crits you'll proc.
Also, the Static Charge is one of the best actives for WK: besides the mana cost (which is rather small), as WK is naturally tanky you'll be able to proc the lightnings lot of times. Plus, you can always Reincarnate! You can consider the Blink-Static Charge-Reincarnate combo an initiation tool that deals mass AoE damage and slow, though you should always try to save your ultimate.
If you're behind in farm or you're simply losing with your team, a cheaper choice made from small components is sometimes better: you won't lose HP because of your Vampiric Aura, and the extra armor and HP regen are all good.
The reason why I don't always pick up an Armlet of Mordiggian is because you can't turn it into anything. Sometimes, though, that's a good thing: there are a lot of situations in which the Assault Cuirass outclasses the Mjollnir, or in which you need a quick BKB or an Abyssal Blade. Just think about what you need and build accordingly.
Wraith King clearly needs more attack speed than damage, as all STR carries. When choosing your items keep in mind the enemy team's composition (such as Heroes that can burn your mana and very squishy Heroes in the enemy lane that you can kill) and build accordingly. If you can farm freely without being killed too often just follow the item build I wrote, else try to take one or more situational items that help you in that specific situation.
These items are the best stats-regen combination you can have if buying a pair of Gauntlets of Strength: since Wraith King's creep damage is low in the very early game, you should take them as a starting item or substitute them with a Quelling Blade.
Everyone should take a combination between Tangos and Healing Salves for health regeneration, no matter what: you might want to use Tangos early on in order to keep your Salve for when you get seriously damaged.
Iron Branches are by far the best starting items: you should probably sell them later unless you are laning against a very offensive trilane, in which case an early Magic Stick (which you will turn into a Magic Wand) is fundamental.
Buy this as your starting item if you're a newer player or simply want to make every last hit count to rush a quick Hand of Midas. The damage increase is useful if you're planning to jungle past level 7 too, I always consider buying it by that point.
If you are sure you'll be laning against offensive enemies buy it instead of the Quelling Blade: most of the time you should avoid picking it (as you usually play Wraith King for farming safely - not carrying the mid game - and the Vampiric Aura should give you sustainability).
Early game items
Talking about Hand of Midas, either you rush it or you don't even think about it: considering that you might switch between jungle and lane when you reach level 7, you might want to take it for the experience and the attack speed increase, which is pretty big for a STR Hero.
Obviously you should try to take your boots as soon as possible, but you have two different choices: Power Treads give you attack speed, movement speed, damage and the ability to Tread switch (I'll talk about Tread switching in another part of the guide), while Phase Boots grant a lot of chasing power, mobility and completely prevent the enemies from kiting you. Depending on the lanes (if you need more early oppression go Phase, if you're farming safely go Treads), pick whatever you feel comfortable with; I personally prefer Phase because kiting really screws up WK.
The Bracer is a small item that helps in transitioning into the mid game: it's like a small Drum and costs slightly more than 500 gold; it also gives you some more damage since Wraith King is a STR Hero.
Take this instead of the Hand of Midas (so, before boots and everything else) if you are against those Heroes that drain your mana. Use it to spam your Wraithfire Blast but remember to use it right before dying: if you don't have enough mana to reincarnate, this will suffice.
I almost never take it, but it's fundamental in a trilane. If I play with friends I'm sure one of them in my same lane will buy it, but most of the time you want your carry to take it since the damage increase isn't part of the aura and only affects its owner. Remember to keep it turned off or you will push the lane.
I talked about this while explaning the usefulness of the Iron Branches, but I'll say it again: if you are against an offensive trilane, this is mandatory. If you have enough inventory space and you're swimming in cash you can buy this, as it would still be useful even after completing your BKB or other extension. Also, burst mana is always welcome for Wraithfire Blast and, especially, Reincarnation.
This is a very underrated item: if you are against a trilane or aggressive enemies Phase Boots and Orb of Venom (very popular on Lifestealer in high level games) leterally crushes the enemies. When your enemies are farming you can just hit and chase them while your teammates reach them thanks to its slow; plus, it can be bought from the side lane shop for a very cheap price. Now that its price is even low, I'm almost considering adding it for the early game item build.
Never forget the Drum of Endurance: it's overused in competitive games, and there's a reason behind it. Depending on your boots, the movement speed pairs well with your Phase Boots and the stats increase plus the extra attack speed maximize the usefulness of your Power Treads; the aura helps in chasing and escaping early on and the same goes for the active ability. The mana it gives is also fundamental for spamming your Wraithfire Blast: the amount of kills you'll get from it will pay for its price.
The Helm of Iron Will is part of the Armlet: you should take it first because the survivability it gives helps staying in lane or jungle.
The Armlet of Mordiggian gives you a lot of good stats that you really need, the only thing he doesn't give you is some mana regen. Remember to activate the Unholy Strength in teamfights or while jungling, so that you can kill the enemies more quickly and they have to deal a lot more damage to kill you.
This item can be used to directly counter those carries that can disable you ( Faceless Void and Naga Siren, mostly) and the one that directly counters you, Anti-Mage: you already are really tanky, and if you calculate that you live twice the damage dealt by autoattacks after activating Blade Mail is huge. Plus, it gives you armor, damage and intelligence, which you desperately need.
The Force Staff is an item that really shines while playing Wraith King, because it can be used in many ways: you can simply use it to escape after you reincarnate or you can drag in your direction an enemy that you stunned and is facing you. Plus, it gives you more HP regeneration and, particularly, more mana. I really recommend it if your damage is already high.
This item is one of the most common mid game items because of its usefulness: as a STR Hero you gain damage (other than survivability) from the strength it gives, too. Buy it if you get focused too often and you can't deal enough damage, but remember that there are some ultimates that go through its Avatar: Dismember, Fiend's Grip, Primal Roar, Black Hole, Ghost Ship and Nether Swap are just some of them.
Personally, this is my favourite core extension: if the enemy towers are still up and you don't get stunned too many times in a teamfight you should buy it, as it reduces the armor of both Heroes and towers. To maximize its usefulness you could use it in conjuction with other armor-reducing spells or items such as Medallion of Courage, Meld or Weave.
This should only be taken if you don't get focused in teamfights and the enemies have either a powerful STR carry or their own armor-reducing item or skill: in this case it's better than the Desolator because it makes you proc your Mortal Strike more often, which results in more DPS. Being able to turn it into an Assault Cuirass makes the armor difference huge.
As you may have read in the Build 2, this build is basically copypasted from the famous Naga Siren mid build invented by Arteezy (aka RTZ): the concept behind it is that Wraith King, being a Hero with a pretty high STR gain and with an ultimate that makes him live twice, is basically indestructible in the laning phase: running him as a safe lane carry with just basic items ( Boots of Speed and not much more) is enough, as he can reincarnate and fight back with the help of his allies if he gets ganked.
After getting a Radiance (usually ~16:30 minutes, but until 18-19 it's still acceptable) you can start farming in jungle more effectively (especially if you decide to put a second point in the Vampiric Aura), then get a pair of Boots of Travel around the 20 minute mark and start teleporting and pushing lanes.
Now, many players might be concerned by the fact that I put a Manta Style not only as a viable option, but as a core item. In fact, there are multiple reasons for picking it: Yasha and Boots of Travel together give amazingly high movement speed and solve WK's famous kiting issue, the illusions carry the Radiance aura and, most importantly, the extra attack speed is needed because of the lack of Power Treads and Armlet; the only downside is that it's AGI-based, but it's still a bit of armor that comes in handy for STR carries.
With this build you need to know when to split push, how (with illusions, by yourself or both) and, most importantly, where. It's a bit tricky to predict where to go, but if you're used to play Heroes like Nature's Prophet or Tinker you can easily make it work.
This is the basic starting set for a melee carry, so you can't go wrong with it. Enough regen to stay in lane until you hit your level 4 and get lifesteal, some stats and a huge damage block.
Never forget the Stout Shield! It makes a lot of difference when you're playing in a contested lane. If you're trilaning or you're sure you'll be fighting versus a melee solo Hero, you can decide to get a quick Quelling Blade instead, but I wouldn't recommend it.
As always, spend the rest of your money on Iron Branches: they're cheap and will stay in your inventory for quite a while because of your slot-efficient (is that even a word/concept?) build, and +2STR and INT can make you survive longer, land an extra Wraithfire Blast, get enough mana to reincarnate and/or last hit better.
Early game items
Again, look at the cheap buildup for the first stage of the game: you want to save as much money as possible, so you only take basic items. The Boots of Speed are a good example: the extra movement speed is something you can't live without, and it only costs a mere 450 gold. It also takes you one step closer (pun intended) to those Boots of Travel.
The Magic Stick is your cheapest option for burst mana, HP and generically sustainability: extra mana, as said before, can mean enough mana to land a stun or reincarnate and the HP, well, keeps you alive.
Lastly, the Quelling Blade: you don't want to miss any of those creeps, so you get something to get easier last-hits. It's also one of the most cost-efficient items if you need to jungle (a thing in which WK, thanks to the Vampiric Aura, excels at) and can save your life if you need to juke behind trees.
When you are in a contested lane, especially versus an aggressive one, the enemies will most likely spam a lot of mana: in this case, spending 200 more gold to get a full Magic Wand that grants 5 extra charges is a safe investment. Especially versus Heroes like Dark Seer, Bristleback and Batrider, you'll charge it up in no time.
Personally, I love this item: I buy it from the side shop as soon as possible if my lane is going really well and I can fight the enemies. The extra movement speed decrease, coupled with the one from the Wraithfire Blast, just works wonders if you have a ganking-oriented support(s) to lane with.
I usually try to stay away from it, but if I'm forced out of the lane very early I get one so I can jungle more efficiently: with a Poor Man's Shield, basically 100% of the hits from the small Satyrs deal no damage, plus the hits from the small Centaur, the small Dark Trolls and generally the creeps in the small camp have a very high chance to deal 0 damage. 300 gold worth the investment, as always.
Take this as soon as possible if you're facing Heroes that drain your mana. Use it to spam your Wraithfire Blast but, especially, remember to use it right before dying: if you never have enough mana to reincarnate, this will suffice. It costs a lot of money if compared to the rest of the items, so even against those Heroes I wouldn't buy it unless I can afford it at the ~5 minute mark.
There are two important things you need to know about these items: you need to get them quickly, and you need to get them in this order. Talking about the Radiance, getting the Sacred Relic (2/3 of a " Power Treads + Battle Fury" buildup) at 14 minutes - or even early - is very easy to do if you switch from jungle to lane when needed; the rest of the Radiance should come very early because of the extra damage from the Relic.
As soon as you have your Radiance, just go ahead and farm your Boots of Travel: after them, you're ready to start split pushing. Getting gold by split pushing, especially if taking towers, is a very simple and quick way to become rich; if you get ganked you still have the Reincarnation, but remember it can't save you if you're under the enemy tower.
Lastly, don't forget about the Manta Style! As soon as you'll buy a Yasha, I'm sure you'll see a lot of improvements: you'll basically transform from a slow and afk-farming Hero to a high movement speed fast-hitter. Completing the Manta Style gives you the opportunity to create illusions which not only scare the enemies when fighting, but can also be used to split push when you run back! They carry the Radiance aura, and even though the extra damage from it doesn't get transferred the aura is more than enough to push a lane and farm jungle creeps (even at the same time!).
The Assault Cuirass is one of the best items on tanky Heroes, and Wraith King is no exception: the attack speed bonus is insane and the armor reduction can compete with Desolator's. Plus it gives you even more survivability and has an aura, so even your teammates gain some of its attack speed bonus. Always remember that late armor is more efficient than late HP on STR Heroes, unless they can summon illusions.
Are you tired of those Phantom Assassins that avoid all your hits or those AGI carries that evade your damage thanks to a Butterfly? Then, the Monkey King Bar is the perfect item for you: it also procs mini-bashes which can ministun a target that is, for example, channeling a spell.
This is the ultimate item for Wraith King. When your team is literally destroying everything, the Heart truly gives you immortality. Twice. With this, you can keep your Armlet of Mordiggian activated forever and you can tower dive taking no damage. Also, as Wraith King is a STR carry, he gains a ton of damage increase aswell. The best situation to take it would be when you or a teammate have an Assault Cuirass or Vladmir's offering (or both), so that you still have some armor.
The Halberd gives strength and evasion, it can slow enemies and it can even make an auto-attacker useless, what else do you need? Also, you need a Sange to make this, which is by itself a good item for a Hero that is subsceptible to kiting.
This item gives you a ton of DPS and even a bit of AoE presence thanks to its Chain Lightning: if you desperately need attack speed and your teammates can keep up with the enemies, this is the right choice. Remember that this effect is an orb that stacks with other orbs: it will only override them when the passive procs, so a Desolator isn't that bad with it.
What? An INT item for a STR carry? Yes, it actually synergizes pretty well with Wraith King: it solves your mana problems, silences those annoying enemies that disable you and it gives you both attack speed and damage! Consider this a viable choice to improve your attack speed, but if one of your teammates is planning to get this don't buy it.
And actually, the Abyssal Blade is a hell of a good item on this Hero: considering you already have a skill that suns, getting another reliable stun can even cripple BKB holders. This is probably the best item to get after a Cuirass or Orchid.
"What? Sange and Yasha? The most inefficient item for its price?" Exactly. After this item became famous on Lifestealer as the best extension if you are already fed, people started noticing its good sides: Drums, Armlet and an extension should be more than enough to deal a big amount of damage if the enemy carry is less farmed than you (remember that you have plenty of built-in damage steroids); if that's the case SnY is the ideal item. More movement speed, more attack speed and the maim ability: I mean, who cares about the damage it gives if you are already hitting for 600HP with crits? It also synergizes very well with Drums and Phase and really resolves your kiting issues. I usually buy the Yasha first as I prefer movement speed, attack speed and a bit of armor instead of raw HP and some damage; that's what competitive players do on N'aix too.
I'll expain these two items more in-depth, as they have different purposes or are weird to see as a viable option.
This is the most high risk/high reward item of the entire game, indubitably. If you have zero deaths or the enemies simply can't kill you, then you should consider this. You are Wraith King, so if you die once you won't lose your Rapier, but you will reincarnate. Also, with this item enemy towers become really weak.
After dying for the first time you should play very defensively for those 60 seconds of cooldown, or you might just give to your enemies a free +300 damage item.
There isn't really anything else to say: if you take this item you should win in some minutes, because nodoby will be able to stop you then. Always have the team behind you though, if you get caught alone it's over.
So, this item is useful and useless at the same time. I like the damage and intelligence increase, but its effect is really dependent on the situation: I never buy it unless I'm swimming in gold and someone else in my team needs an Aegis of the Immortal, as I would be wasting 5300 gold (and 375 mana, which is a big deal) to resurrect 60 seconds before, 60 seconds in which I could even play without dying.
Many guides recommend this, and it surely deserves a paragraph, but let's say it's not a choice that really shines on Wraith King. Other Heroes, for example Zeus or Warlock might make better use of this, considering that they need the HP regen and the intelligence increase more than a carry. They also have a large mana pool to activate it and still be able to cast their spells, most of the time.
Items to avoid
Don't even think about it. When using a Crystalys the critical hit chance won't stack with Mortal Strike and with just 350 more gold you could buy a Demon Edge which gives +46 damage (which is a lot compared to the +35 damage increase from Crystalys) and can be used to make either a Divine Rapier or a Monkey King Bar. Same thing for the Daedalus: it costs more than an MKB but doesn't either mini-stun or deal true strikes. It also gives you less damage without counting the small crit chance increase.
Just why? You are a carry, carries don't buy Bloodstones. I understand that you might need more mana, but then why don't you get a Scythe of Vyse? The Hex ability will be a lot more useful than a quicker respawn, especially because you can reincarnate.
As I said before there is only one way to play him as a carry, you can't go wrong with this build. You max out Wraithfire Blast together with stats and one point into Reincarnation and Vampiric Aura so that you can do as much damage as possible with it in the early game and still have some regen. Then, you max out Mortal Strike and finish levelling Vampiric Aura.
Wraithfire Blast is the skill you want to max out first because it does a fair amount of damage in the early game which, coupled with the stun, slow and damage over time, ensures a kill on a weakened enemy.
Mortal Strike is the classic critical hit proc which shouldn't be skilled if not after level 7 because, I know I've said it a lot of times, it deals minimum damage in the early game, which makes stats a safer option.
Vampiric Aura makes your lane push, and you don't want it, so you either put one point in it at 4 for the extra regen (which is better with a competent support that pulls costantly) or don't skill it at all before maxing out the other two abilities.
Reincarnation should be taken as soon as possible, so at level 6, 11, and 16.
*Optional: you aren't supposed to jungle in each match you play, it really depends on your team composition and farming.
Wraith King should lane very agressively unless your team can push and (especially) counterpush relatively easily. Plus, you should minimize your deaths because every time you die you lose gold (which you really need), experience and creep kills/denies.
While playing with a carry you should always head to the safe lane, or short lane, which is bot for Radiant and top for Dire. Also, you must lane with one or two teammates that can disable the enemies very effectively.
I like trilaning with Wraith King for one simple reason: he has a reliable single-target stun, which very few carries like Sven and Chaos Knight have. Some good trilane lineups that should work (I've tested some of them) are the followings:
Wraith King - Sven/ Naga Siren - Shadow Demon
This lane is more than enough to kill enemy Heroes that are too confident when stepping close to your tower: Shadow Demon can use his Disruption and Soul Catcher to make everyone squishy, while Sven's Storm Hammer stuns and deals damage for a long duration against trilanes or Naga Siren's Ensnare secures kills against slippery solo laners. Obviously, the Wraithfire Blast makes everything easier and grants easy kills from a distance, considering that both Sven and Naga Siren either autoattack pretty hard by themselves or have an extra nuke that makes autoattacks easier.
Plus, you can go to jungle at level 8 and let the Sven or Naga Siren farm in the lane: Shadow Demon will discourage enemy ganks thanks to his abilities.
This is a controversial topic, because you should behave differently basing on the type of gank:
When you are ganking the enemies in your lane you should be chainstunning after one of your lane partners engages: with your Wraithfire Blast, because of its damage over time and stun, you can get an easy kill after you land it. You shouldn't find it difficult to go into the fray first either, thanks to your survivability and your "second life" just remember that if you are planning to gank at night some enemies have different sight range. You can see all the exceptions here.
When your teammates are going to gank a lone enemy, don't go with them: why would you leave your reliable resource of gold and experience, especially when there are no teammates nearby that steal half of the experience you get? Of course if you are fed you can go to help, or if your teammates really need your stun you can temporarily leave your farming spot and go, but no-one recommends it for a hard carry. Don't gank lone enemies if not really needed.
When you reach level 7-8 you could go jungling, which is a nice choice especially if you have bought a Hand of Midas and your lane partner(s) can keep up with the enemies without your help.
While jungling always take a look at your lane, because you may go to gank Heroes that come too close to your tower. Especially, if you have friendly Observer Wards nearby, you will find it really easy to kill bad-positioned enemies.
If you have a Hand of Midas always select the biggest creep, so that you'll get a lot of experience.
This is the moment when any carry shines: someone for his enormous cleave/AoE damage, someone else (like Wraith King) for his quick DPS and chasing capabilities thanks to early-game items.
In teamfights you must let your team initiate the fight: if nodoby stuns you, you are unstoppable. With your big DPS - granted by your Mortal Strike - you can kill everything in a matter of seconds; the real problem is that you have no AoE presence: you can obviate the question by having teammates with a big AoE potential or by trying to engage versus a small number of enemies.
Remember that you can Reincarnate: even if you literally suicide for an enemy, as long as your teammates won't leave you alone while you reincarnate you are fine. Don't forget about this, which is the best feature of the Hero!
What is Tread switching? Basically, it means switching the attribute of your Power Treads so that you can maximize their usefulness. Here is a video talking in-depth about it:
If you don't have enough time to watch the entire video, I'll tell you the most important things.
First, remember that while switching attribute your mana and strength will change basing on their percentage. For example, let's say your maximum amount of mana is 100 and, while switching to INT, is 120. If you have 50 mana (50%) before switching to INT, when you switch you'll have 60 mana (again 50%). That's why while using regeneration items you must always set the Treads to AGI, so you can gain a bigger overall percentage of health and mana.
Switch your treads to INT before a teamfight: If so, your mana pool is bigger and while using Wraithfire Blast you'll consume a smaller percentage of mana. So, when you switch back to STR you'll end up having more mana.
Switch your treads to AGI while regenerating: when using items such as Healing Salve, Clarity or even a Bottle for mids, always remember to switch your Treads to AGI: if they are on INT you'll gain a smaller percentage of mana from Clarities and Bottles; if they are on STR you'll gain less health.
Switch your treads to STR while farming/teamfighting: as you are a STR Hero, you need more damage when farming. Plus, as with Wraith King your primary attribute increases your max health too, you want to keep them on STR even in teamfights for the extra HP.
Wraith King needs laning partners that can secure kills, while in teamfights he needs someone to initiate before him. If he gets good farm early on he truly becomes unstoppable.
If you are in a trilane (which is the most common lineup for a competitive match) you could aim for the hard lane and pair with two aggressive supports: remember that at least one of them must be a ranged Hero. You can also try to do a safe trilane if you're playing support and there's a solo off-laner in the enemy team, so you can roam: WK is an excellent roamer, especially with a partner with another disable. Some Heroes that work wonders with Wraith King are:
Quick tip: you can get a support that can easily transition into a semi-carry (or full carry) like Sven or Naga Siren, so that you can start jungling at level 8-9 and let them farm in the lane. I've seen this tactic with Phantom Lancer more than once, back in the days when he could jungle effectively with a pair of Tranquil Boots and a Soul Ring.
In teamfights you should wait for your initiator to start the fight, then you can run into the enemies and kill everything. Or, if you have a Blink Dagger, go in first and let them follow up. Try to play with big teamfight contributors that make your job way easier:
Wraith King doesn't have any other foes (except for Doom Bringer, which is everyone's foe), because the real thing that makes him a good or bad carry is you: if you can't farm well and miss easy kills in the lane, you are going to have a bad time in the mid/late game. Wraith King is a carry, and that has its pros and cons: obviously, if it seems you can't play well at all it can't only be your fault, maybe your lane partner(s) can't chainstun properly or the enemies deny a lot of experience and money from you, but it's in these cases that the best carry players reveal themselves.
Long story short: don't give up if you don't farm succesfully, just try to improve as the game goes. It's not your fault if you don't play well, the whole team has its own successes and defeats. Or well, you can blame that Russian guy that played Anti-Mage and bought a Helm of the Dominator.
06-19-2014: Added an explanation for the semi-carry build.
05-25-2014: Added the semi-carry and hard support builds.
02-22-2014: Added TC's split pushing Wraith King build.
12-16-2013: Big update: now the skills are linked to Wraith King. Also, updated the skill build.
06-27-2013: Updated the guide following the current meta; lots of improvements.
02-12-2013: Added a free farming skill build.
02-12-2013: Remade the "Playing Style" chapter, partially.
02-12-2013: Remade the "Friends and Foes" chapter.
12-17-2012: Added the Diffusal Blade between Wraith King's foes, as suggested.
12-15-2012: Added the "Playing Style" chapter.
12-14-2012: Added the "Tread Switching" chapter.
12-13-2012: Added the "Skill Build" chapter.
12-13-2012: Added the "Friends and Foes" chapter.
12-13-2012: Wrote the first part of the guide.