The next requirement includes acquiring the achievement You Are Now Prepared. This will also be required for getting to Argus, where you will continue your journey in unlocking this race. Spare being a Horde-only player, most should already have this one covered.
The first requirement is to hit level 110 on an Alliance character. To unlock the Void Elf race you will only have to complete three steps, though each will be more of a time investment than the last. From here she has worked to create one of these new allied races, the Void Elf. During the events on Argus, Alleria Windrunner, hero of the Alliance, became the first mortal to harness the powers of the void. The World of Warcraft: Battle for Azeroth expansion is out on Augand with it, is the addition of a variety of allied races to play as.
