So, if you have one of these meatbags, what are you supposed to do with them? It's hard to say what the original intent of the developers was when they decided to add this guy to our arsenal. We can do this with most of the others -- the imp is a ranged damage dealer, the succubus is for melee and CC, the void for tanking and the puppy for annoying mages. The felguard joins the show and not only deals a whole load of damage he can also take a huge amount as well. As such he pretty much makes your voidwalker and succubus obsolete.
This hasn't always been the case. The voidwalker used to have a massive advantage when tanking through great scaling of stamina and armor as well as having a threat generating ability that could really hold some attention. Then came Sathariongate. Tanks have a hard time in the game. When it comes to instances, they just don't scale well. That's not a comment about their abilities or gear, it's about how many you need -- 20% of the group in 5-mans, 10-20% in 10 mans and 8-12% in 25 man raids. So the bigger the instance you want proportionally fewer tanks (yes, I know those figures are not absolute). So when a voidwalker was shown to be the most effective tank for Sartharion (with drakes remaining) you can well imagine tanks being not too chuffed about being dropped from raids so a blueberry could take their place. This led to voidwalker threat being nerfed to pretty useless levels and stamina dropped to the same level as any other pet besides the imp.
This actually had almost no impact on raiding. The voidwalker could still tank Sarth (it was just harder and tanks were getting better gear anyway) and that was the only fight they were any use for (since the DPS were killing something else for the time the void was tanking). It did have a profound impact on solo play though. I don't have any access to figures about how many voidwalkers are summoned but I wager that after these changes if anyone had access to a felguard through their main or off-spec they used him instead. Maybe that tells us that the developers were looking for the felguard to be the damage minion in raids and the tank for solo play.
He certainly is the damage dealer in raids, doing more than twice that of any other minion you can bring. Indeed, you can expect over 20% of the damage you do in a raid to come from this guy. As we saw in the Blood Pact article about it, he also works very well with providing the Demonic Pact buff. Add this to the changes we are seeing in demonology damage potential and I think we're going to be seeing more felguards in Icecrown Citadel very soon.
Out in the wilds, when it's just you and your minion, just how useful is he? As it happens, he's immensely useful. As I've said, he is a very capable tank, a large part of his threat generation is based on his damage (which we know is decent) but he also has Anguish to raise his threat level further. Don't get carried away though, if you blast out your spells you will gain aggro and with no Misdirection ability there's not a lot you can do other than Soulshatter and slow down. Unlike the voidwalker he doesn't have an AoE taunt but instead he has Cleave. This isn't going to fixate extra mobs for long but it does mean he can get their attention while you set him taunting through one at a time.
At level 52 your felguard will learn a neat new trick called Intercept
. Now, this is one of those abilities that I generally just left on auto-cast when leveling but I think I was missing a trick here. If you do have it auto-cast then he'll use it whenever he can, typically to start a fight all the sooner, and start it with a stun. This is good but it means that it will often be on cooldown when you could make use of it. The best time for that is when some other mob makes a run for you. This could be because you moved into their aggro range or they peeled away from the group the felguard was fighting.
What you want to have then is a means of getting that mob back onto the felguard and stopping it from molding your face to the shape of whatever weapon they are swinging. You can do this with a simple macro:
/cast [target=mouseover, exists] [exists] Intercept
All you need do is hover your mouse over the errant mob and press the button bound to that macro. Assuming the felguard is at an appropriate range (between 8 and 25 yards) he will dash over and stun it. This will change the felguard's target but not yours, so if you want to put him back on to your target you need to send him in again (always worth having '/petattack' bound to a hotkey).
They have a couple of other abilities that you simply don't ever need to worry about, Demonic Frenzy
means that he does more damage the longer he's been hitting stuff and Avoidance
means he shrugs off all but the most crazy-serious AoE damage. These are passive abilities and are always 'on'.
In short, the felguard is a real power-house mixing survivability with raw damage output. He's a great leveling companion, he turns a lock into a group (able to take on all but the toughest group quests) and is becoming one of the must-have accessories in raids. All hail the mighty felguard!
Final words go to the classic Felguard Poem
Blood Pact is a weekly column detailing DoTs, demons, and all the dastardly deeds done by Warlocks. If you're curious about what's new with Locks since the last patch, check out WoW.com's guide to patch 3.3 or find out what's upcoming in Cataclysm from the BlizzCon 2009: Class Discussion Panel.