FOund this:
Why am I doing a pet guide for the Warlock? Because every single piece of info I have heard from players about the Fel Hunter is WRONG!
When I hit 30 I could go after the Fel Hunter quests, but I did not because I had heard numerous times that it was totally useless. So,(like a dumb ass) I ignored the quest. I had messaged no less then 10 lvl 50+ Warlocks and had asked about the Fel Hunter and not a single one, without exception, knew wtf they were talking about.
The pets:
Imp:
Pet intent = to get you a soul stone.
The Imp is only there for 1 reason and that is to get you a soul stone for a better pet. It has a few skills such as giving the warlock a fire shield that is auto casted, and a stamina buff "bloodpact", as well as going invis while not in combat. The HP of the Imp is tiny and damage output is "O.K." until he runs out of mana.
Voidwalker:
Pet intent = PvE leveling.
The Voidwalker is a PvE master, having an awesome taunt, as well as AOE taunt later on, it can also heal itself after a kill, out of combat. Having massive HP and Armor, if you are on a PvE server this pet will do you just fine all the way to 60. PvP is another matter, you can sacrifice the Voidwalker for a damage shield, but Warlocks cannot stay in melee for more then a few seconds. Wearing cloth with mediocre HP is very melee unfriendly. Damage output of a Voidwalker is very small though.
Succubus:
Pet intent = PvP defensive.
The Succubus can "almost" hold her own in PvE, damage output for a pet being a little above average. The Invis ability lets her get close to a mob without getting agro early. For PvP she can be use full if played correctly. Always run with your Succubus invised as I have had nooblets run up and try to PvP me thinking I have no active pet. Most peeps I see use the "charm" which basically takes the target out of the combat equation.(if you already casted your DOT's it will break the charm, only use charm in the initial seconds of combat) After you charm the peep, go to max range and unload, telling the pet to attack only after you see charm break. If they try to melee or cast then simply fear, shadowbolt, shadowbolt, and fear again.(repeat if necessary) If you are facing a caster the curse of tongues may be better for you then Agony, but I do not think that works against insta casted spells. The Succubus has light armor and light HP which is balanced by her above average damage output.
Fel Hunter:
Pet intent = PvP offensive.
The PvP Master!(you heard it hear first, LOL) The Fel Hunter has a little better armor and HP then the Succubus,(not much) but does less damage. The initial skill is a debuff, which every time the Fel Hunter is hit it debuffs the targets attack power. It stacks up to 5 times and seems to proc, if not every time it is hit, then most times. Of course this is a PvE skill to get the mobs damage and chance-to-hit down in case the Warlock gets the agro. The Fel Hunters low damage means that it cannot hold agro for more then the first 5-10 secs of combat, if you are hard core nuking. Now the second skill is a "Magic debuff", every 8 seconds you can click this skill,(it is not auto casted) what this does is takes away 1 "Magic buff" from the target. The Mages INT buff, gone... the Priests stamina buff, gone... From my experience with the Fel Hunter anything that says "Magic" in the mouse over of the skill can be taken away You can also use this to take away those nasty DOT's that are on you You must target yourself and click the skill though. You can also use this as a "griefer pet", you know all those potions that peeps use that give them +AGI or +STR and other buffs? Most of these are "Magic", and if you debuff it, then you just cost your target some coin, since they either made the pot or bought it Oh, I forgot, if you are in PvE and you debuff your target,(assuming the mob has a buff on) it heals the pet. It also heals the pet in PvP, but I am assuming that no one hits a pet in PvP so healing it when it is full does nothing. The second skill is "spell lock", this one can be set to auto cast. When you use this skill it stops the caster from casting the spell he/she is casting and "locks" out that spell line for 8 seconds!!!
How to use the Fel Hunter.
As I have said the Fel Hunter cannot hold agro, so when you send the pet, and dump your DOT's, watch the pets health, if it needs a heal click the "debuff skill" on the pet bar, if the mob had a buff on it that was debuffed then you pet will get 243 health.(not exact on the number but its over 200). Most likely though, the pet will lose agro quickly and the mob will come at you, now you want to click the debuff, because this seems to work like a "mini taunt" on the mob. If the mob is still coming then fear it or life drain it, don't fear it, if it is in a high mob population area. You did place those talent points so that the "lifedrain" has a 70% chance to not be interrupted right? If facing a caster mob then click a single DOT, before sending the pet. Since I leave the "spell lock" on auto cast, if I send the pet first he auto casts spell lock before the mob casts which makes the skill useless. I cast a single DOT, the mob agro's me and starts to cast, then I send pet, the pet will auto cast spell lock on the mob interupting it, and then just unload on it. In PvP remember, never send the pet first,(unless you want to turn on the "spell lock" skill AFTER the target starts to cast) and don't forget to debuff them
I am sure there is a 3rd skill but I am not that high of a lvl yet