World of Warcraft®

While off cooldown, your Dark Soul ability passively grants you 10% of the active effect, but reduces the power of Dark Soul by 10%.

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.

Splits your Shadow Bolt into three smaller attacks.

Your Hand of Gul'dan can now be targeted at a location.

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