World of Warcraft®

Requires Demonology.

Teaches you the ability Dark Apotheosis.

Dark Apotheosis
You imbue yourself with demonic energies, reducing physical damage taken by 13.85%, reduces magic damage taken by 15%, and allows the use of various demonic abilities.

In addition, Soulshatter becomes Provocation which taunts your target, Twilight Ward becomes Fury Ward which will absorb all schools of damage, Shadow Bolt becomes Demonic Slash, and Fear becomes Sleep.

You restore 20% of your total health after you kill a target in Demon Form that yields experience or honor.

Teaches you the ability Imp Swarm.
Requires Demonology.

Imp Swarm
Summons 5 Wild Imps from the Twisting Nether to attack the target.

The Wild Imps passive effect is disabled while Imp Swarm is on cooldown. Imp Swarm's cooldown is reduced by spell haste. Also increases Wild Imp's cooldown by 4 sec.

Your Carrion Swarm no longer knocks targets back.

If you use Demonic Leap while falling, you slam into the ground rapidly and will not die from falling damage.

Your Felsteed and Dreadsteed can cross water while running and leave a trail of flames.