Codex of Xerrath (ability)

The Codex of Xerrath is a passive ability that infuses a number of Warlock fire abilities with fel magic, turning them green.

Spells affected by this ability

 * Rain of Fire
 * Burning Rush
 * Metamorphosis (warlock ability)
 * Hellfire
 * Wild Imps
 * Immolate
 * Ember Tap
 * Conflagrate
 * Incinerate
 * Flames of Xoroth
 * Metamorphosis (warlock ability): Immolation Aura (warlock ability)
 * Soul Fire
 * Felsteed (warlock ability)
 * Dreadsteed
 * Summon Abyssal
 * Demonic Fury
 * Dark Apotheosis
 * Demonic Leap

In addition, Chaos Bolt, which is green to begin with, becomes larger and resembles Kanrethad's empowered version.

Also for Destruction Warlocks, the Burning Embers UI graphic turns green.

Unlocking green fire
The ability can be unlocked by defeating Kanrethad Ebonlocke at the end of the Pursuing the Black Harvest scenario. (see Kanrethad Ebonlocke (tactics) for further details). Once unlocked it can be toggled on and off at The Hand of Gul'dan.

Switching between green and orange fire
Once the ability is unlocked, it can be turned on by siphoning fel magic of a banished Kanrethad at the Altar of Damnation near the Hand of Gul'dan at Shadowmoon Valley.

To turn off the effect, speak to Jubeka Shadowbreaker who is also at the Altar of Damnation and ask her to remove the fel corruption. This will return your fire spells to their default color.

Patch changes

 * The Codex of Xerrath now infuses additional spells with fel magic (green fire effect).