Warlock Green Fire
The Warlock Green Fire is a special visual effect for Destruction Warlocks, that you unlock after completing a series of warlock-exclusive quests related to the Council of the Black Harvest.
After defeating Kanrethad Ebonlocke and completing the Pursuing the Black Harvest scenario you will learn https://www.wowhead.com/spell=101508/the-codex-of-xerrath, a passive Warlock ability that corrupts all of your Warlock fire spells, infusing them with fel magic.
Warlock Green Fire Questline
To start the questline you will have to use the Sealed Tome of the Lost Legion
in combination with a Healthstone. This tome drops from rare mobs on the Isle of Thunder, but you can also purchase it on the Auction House.
The tome can only be looted by Warlocks, and upon accepting or completing the quest, that character won't be able to obtain the tome again. The quest chain is the following:
- https://www.wowhead.com/quest=32311/ for Horde; https://www.wowhead.com/quest=32312/ for Alliance
- https://www.wowhead.com/quest=32309/ for Horde; https://www.wowhead.com/quest=32310/ for Alliance
- https://www.wowhead.com/quest=32314/ for Horde; https://www.wowhead.com/quest=32313/ for Alliance
Upon completing the quest chain, you will learn https://www.wowhead.com/spell=101508/the-codex-of-xerrath. Anyone that was fortunate enough to complete this prior to the release of Warlords of Draenor, also got the https://www.wowhead.com/achievement=9016/breaker-of-the-black-harvest FoS achievement and "of the Black Harvest" title, which are both now unobtainable.
You can turn the fel fire effect on and off by visiting https://www.wowhead.com/npc=70270/jubeka-shadowbreaker in Shadowmoon Valley.
/way Shadowmoon Valley:Outland 42.6 43.9