Warlock's Infernal Pets

At level 50 you can get the Infernal. The quest is extremely hard to solo until the high 50's, so you may need help. The infernal is not a pet you will be using frequently, seeing as it can only be summoned once per hour, it requires a reagent, and it breaks free after 5 minutes.

The spell to summon the infernal has a 2 second cast time, and when the infernal lands it will deal a small amount of shadow damage to all enemies around it as well as stunning them for 2 seconds. The Reagent needed to summon one is called an "Infernal Stone"

The infernal comes with a good chunk of health, fire immunity, fear immunity, and a permanent immolation aura that deals fire damage to every enemy around it every 3 seconds. It also hits pretty hard, and tanks well in PvE if you ever decide to use it for that.

Its fear immunity makes it a useful tool against enemy priests.

The infernal is useful for attracting attention in group PvP. If you send your infernal in to attack an enemy group, chances are they will focus their firepower on the infernal, giving your group members an easier time.

Prior to a certain patch, the summoned Infernal would roam free. Now, he comes enslaved after summoning and will break after five minutes.

Before patching, the only way to get the ability to summon an Infernal was to find a Book in Lower Blackrock Spire (LBRS). While the book is still available in LBRS, the spell can also be learned through a quest chain in Bloodvenom Falls, given by Niby The Almighty. After defeating Kroshius (55 Elite Infernal) and El Pollo Grande (Niby's summoning, non Elite) you will get the spell.