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.

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.

Improves your demon's special abilities:

Your Imp's Firebolt cast time is reduced by 50% and fires in bursts of three.

Increases your Voidwalker's total armor by 10%.

Your Succubus's Seduction ability also removes all damage over time effects from the target.

When your Felhunter uses Devour Magic, you will also be healed for that amount.

Increases your Felguard's total health by 20%.

Your Felguard will equip a random two-handed axe, sword or polearm from your backpack.

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