Warlock is an unusual hero - with some unique skills. While a good support hero during the laning phase, his true potential can only be unlocked by fighting with his teammates.
He's very potent at early harassment, especially against evasive heroes like Weaver or Windrunner who can avoid auto-attacks.
He suits players with good positioning and tactical sense, who enjoy co-ordinating with their team. Hes a poor choice if you like to farm and want a big number in your kills column.
+ Good starting strength and growth
+ Good starting intelligence and growth
+ Excellent team fight skills
+ Not farm dependent
+ Fast attack animation and projectile speed
+ Long range initiation
+ Good babysitter
- Poor starting agility and growth
- Long cooldown time on spells
- Abilities slow to take effect
- Very long cooldown on ultimate
- Ultimate is his only stun
- No escape mechanism
Fatal Bonds is an excellent skill which holds its value throughout the course of the game. Every enemy linked by the bonds will take 20% of the damage suffered by the others, making it absolutely devastating when combined with big AOE nukes from your team.
During the laning phase, you can use this spell to harass enemy heroes, and to push the lane out where required. It inflicts good DoT harassment, but be aware that it will move the lane away from your tower.
During ganks you should attempt to bond together enemy heroes whenever possible, or just to creeps if necessary. This extra damage can make the difference between getting a kill or not, as the bond has no range limitation. It also makes it difficult for enemy heroes to juke, as the bond will show where they are.
During team fights you should always attempt to link the enemy heroes as quickly as possible, the damage boost is massive, and can also kill off enemy heroes who attempt to flee the fight on low health. Bonds is your main damage skill and scales extremely well.
Fatal Bonds is your only real farming spell - you receive the gold for any creep killed by the fatal bonds damage rather than a direct attack from another creep or player.
Bonds works by a rare form of damage known as "HP Removal" - this subtracts damage directly from a player and is extremely difficult to block or reduce, however it doesn't trigger an "attack effect" on the player, so does not stop abilities like Blink Dagger cooldown.
Shadow Word is your Heal and Damage spell depending on whether you cast it on a friend or enemy. I cant really call it a Nuke as it takes 9 seconds to inflict all of its damage :-).
Shadow Word is useful early game for healing yourself or your lane partner, slowly building the HP back up. It can frequently let you survive close ganks, and can let you successfully bait enemy heroes into bad situations - the only issue is that the heal is slow acting, so it proves ineffective against big burst damage.
You can also use it to harass too, and can even get you unexpected kills if you cast it as an enemy is retreating. The combination of Fatal Bonds and Shadow Word does a deceptively high amount of damage.
Later on in the game, you can use it to heal up your team and weaken enemies, but is a low priority compared to your other skills in a team fight.
A very powerful and highly under-rated spell that is practically a 2nd ultimate in terms of its AOE, cooldown (50 seconds!) and potential effect. It also has to be channelled, which means it should usually be cast 3rd after Fatal Bonds and Chaotic Offering in a team fight.
Upheaval has a very large area, but it takes time for it to really build up effectiveness. Depending on the level of the spell, every second you cast it increases the amount of slow by 7/14/21/28%, up to a maximum of 84%. Hence it takes 12/6/4/3 seconds to reach maximum effect. Enemy heroes are also slowed for 3 seconds after they leave the AOE of Upheaval.
Upheaval can really mess up enemy teams who pick too many melee heroes, although heroes with either a blink ability or dagger are much less effected. You can also use it for early ganks and escapes - its a little impractical, but can be surprising effective - how many other skills offer the potential for a 13 second 84% multi-target slow?
This is Warlocks showpiece skill, combining a massive AOE stun with damage and free minion(s). This is a really great initiation spell, as you can cast it from long range, allowing you to stay out of trouble while opening the door for your team.
Chaotic Offering has a 1 second stun that bypasses magic immunity, and inflicts 100 damage at all levels. It will also summon an Infernal, one of the strongest minions in the game, packing a radiance-like effect, plus good damage and hit points. Be aware that enemy heroes can claim 100 gold for last hitting it.
The Infernal is great for attacking enemy heroes while youre busy channelling Upheaval, and can also be used for farming and tower pushing afterwards. Buying an Aghanim's Scepter will mean the spell summons 2 Infernals instead of one, but their hp and damage are reduced by 25%. With a Refresher Orb you could potentially have 4 Infernals at once :-)
On the downside, Chaotic Offering has a long cooldown time (nearly 3 minutes) and should not be wasted. Early game, the ideal time to use it would be to initiate on the enemy lane heroes, and then push straight on to their unguarded tower. Later on you should only really be using it for team fights, and the Gollum does lose some of his impact against strong carry heroes.
Be aware that the active purge from Diffusal Blades and Shadow Demon's Demonic Purge can insta-kill your gollum - this is bad.
Your combo was made for team fights ideally it should go:
1) Fatal Bonds
2) Chaotic Offering
However, sometimes the situation requires you to cast Chaotic Offering first to get the stun, then follow up with Fatal Bonds and Upheaval.
If you have a Refresher Orb, make sure to cast both your other spells again before launching in to Upheaval.
Getting your Chaotic Offering right is the most important thing - you need to hit multiple targets and give your team a window of opportunity. This can make a big difference whether you're initiating or counter-initiating. You don't need to worry about enemy magic immunity - the stun goes through even if the meagre 100 damage doesn't.
In some games when against heroes with big team fight powers like Enigma, you can end up playing a game of cat and mouse about who initiates first - don't be afraid to keep out of trouble and with your ult in the bag to stop them from using theirs.
Warlocks biggest issue is mana - you can't afford to be too wasteful - remember his right click is good for last hitting/denying/harassing. Early game is about managing these costs until you can some additional regeneration, usually Arcane Boots and some levels will do the trick.
While you can be played in different ways, you're usually a support hero, and should always be prepared to help your team out by buying items such as a Animal Courier or Observer Ward, plus utility items later on. In most lane setups you should allow your partner to farm, concentrating on denial and harassment. You can grab some farm when you get the chance, but you should concentrate far more on teamfights and pushes.
Once you've solved your initial mana problems, you should concentrate next on utility items depending on who else is on your team. If there are heroes already doing this, you may be able to go straight for your luxury items.
Obviously everyone has their own favourites, but personally I like this:
2 x Clarity (100)
2 x Iron Branches (106)
Animal Courier and Observer Ward (300)
As a ranged support with a good attack animation, you can generally stay out of harassment range, allowing you to heal yourself or your carry as necessary with Shadow Word. The branches provide a cheap boost to your stats, and can be used for your Mekansm later on.
Your priority when looking at your core is to boost your mana regeneration as quickly as possible - allowing you to make more use of your spells.
Arcane Boots give you an occasional boost of mana, and once you have some levels up, its usually enough on its own. They're also a useful item for the rest of your team. On the subject of boots, there are other choices available depending on your playstyle and team setup but you should always have at least boots of speed.
Ring of Basilius is another team item, giving you and nearby players some extra mana regen and armour. However, I dont think its really enough on its own. Again, be aware how many other players on your team already have one, or will be getting a Vlads.
Magic Wand another item giving you some cheap stats boost and health/mana on tap. However, it probably wont cover your needs on its own unless youre laning against Zeus or Shadow Demon.
Bracer - a basic stats item to improve your damage and survivability. Null Talisman is also an option, but you don't really need the extra intelligence or damage. Dagon is not a good choice on Warlock, Drum of Endurance is a much better utility item.
Depending on the way the game plays out, and your slow farming speed you wont necessarily get the chance to buy all of these items, but here are some of the options.
Unless someone else on your team (e.g. Lich, Dazzle) has already got a Mek, or its too late in the game for it to be effective, you should be aiming to get one for your team. Its regen and auras are useful for you, and you should be at all the team fights when its needed.
Drum of Endurance:
Another good team item, it boosts speed and attack speed for you and nearby allies, plus providing some nice stats gains. Its a solid item choice if your team doesnt already have one.
A useful enhancement to the Ring of Basilius, you should only really consider it if you have melee heroes on your team who will benefit from the lifesteal. However, the various auras are still useful, and will benefit your minions.
Eul's Scepter of Divinity:
At just over half the price of a Sheepstick it only provides boosts to movement speed and mana regen. The cyclone ability allows you to temporarily take one hero out of the game - very useful if you need a bit of escape and some extra disable.
Due to your support status, relatively poor farming speed, and that you might have been buying wards and dust all game you may find expensive items difficult to acquire. If you can afford one, its important to get the choice right:
A very solid item; gives you a lot of stats and further improves your Ultimate. This used to be a big no-no on Warlock due to some unknown bugs - this has now been fixed, and the Gollums now function as intended. A Refresher Orb is still preferred if you can afford one however.
An extremely expensive item, but it adds a lot of intelligence/mana related stats, and gives you the ability to instantly cooldown your skills. This is very, very useful for Warlock, allowing you to use your ult twice in one fight, or to minimise it's cooldown.
Warlock benefits from the extra strength and intelligence provided, and can make good use of the minions. However, he may struggle to afford the upgrades that really benefit this item such as invisible hero detection - make this a priority if your team needs reliable detection.
Scythe of Vyse:
Or Sheepstick, this item is very powerful, but expensive. It adds a lot of power to your right-click, and gives you an extra hex ability. However, neither of these can be used while channelling upheaval. Ideally there will be someone else on your team to carry this instead, but in specific situations (e.g. against the likes of Storm Spirit, Anti-mage etc) it may be vital.
Any DPS or Orb items are not recommended due to your poor agility.
Warlock is a great hero when the opposition has gone for a melee heavy team, especially if they are not usually blink dagger users. Upheaval will really let your team dominate fights in this situation.
Warlock is a good support pick, and especially good at supporting carries who have a hard time in the lane at the start. He synergises well with DPS heroes and heroes with big AOE nukes - adding 20%+ damage amplification to the likes of Echo Slam or Poison Nova can be deadly. Each hero bonded will take extra 20% damage from each of the other ones hurt!
Special mentions go to Venomancer who's ulti can be lethal combined with bonds, as well as Witch Doctor who synergises extremely well with your skills. Sand King is another hero who really benefits, and is a dangerous laning partner. Generally any hero with big AOE damage will get on well with you.
Warlock is unusual in that he provides ranged support and initiation.
Warlock doesn't really have a direct counter as such, but he's somewhat vulnerable to anyone who can get and stay close. He has no real escape mechanism and although reasonably tough for an intel support...he's still an intel support.
Characters with blink abilities (or likely dagger wearers) are much less affected by your upheaval, as its a slow rather than a stun, and they can just disappear out of it. Strong ranged carries like Gyrocopter are also less bothered as they can continue shooting, even if they find it difficult to escape.
Shadow Demon is worth a mention as his ultimate can insta-kill your gollum with it's purge - the same with the active purge on Diffusal Blade.
Although Warlock is reasonably sturdy, he's unlikely to have the items to turn him into a real tank, so gankers such as Pudge and Nyx Assassin can do serious damage - plus they have stuns that will stop Upheaval being channelled.
All of the above are manageable to a point, but the real reason not to pick Warlock is if your team is desperately in need of Stuns.
I'd keep an open mind when it comes to your skill build with Warlock - you should adjust your choices to the situation rather than stick religiously to one set build. All of your skills are useful, it's just a matter of deciding which ones you need to level most urgently. I wouldn't describe 'lock as a min/max hero, you can spread your points around a little depending on what you need.
As a general rule, you should always get Shadow Word to at least level 2 fairly early on - it gives you and your allies sustainability in lane, and allows you to harass without pushing the lane.
Fatal Bonds is no doubt your best skill, and the mana cost doesn't increase as you level it - however, it will push the lane. You can make this work for you with effective stacking/pulling, or if you want to try to take towers early. It's horrible for enemies to lane against as they can't avoid the reasonably substantial damage. You need to have it maxed by the time serious team fights break out.
Upheaval is more tricky - some 'locks don't level it at all, choosing stats instead, some players absolutely love it. How effective this spell is really depends on the opposition - if they don't have any way of easily escaping or avoiding it's effects, then it can be devastating, especially against melee heroes. Against teams who have skills that bypass it, then it's a low priority. If you're going to get it, commit at least 2 points to make it worthwhile.
Chaotic Offering - easy one, level it every chance you get - the mana increase is fairly negliable, and the gollum much more effective.