Host of the Eternity King

The Host of the Eternity King is the third army to be released as part of The End Times supplements, appearing in the End Times: Khaine splatbooks. Since the Khaine books aren't out yet, this article is based on leaked content and is going to need to get properly set up once they're out.

In short, the Host of the Eternity King is stemming from the reveal that Malekith was always supposed to be Asuryan's chosen Phoenix King, he simply wimped out one second too early. Because of this, and the severe fuckery that Nagash and Chaos are up to, all three forces of elves -- Asur, Druchii, and Asrai -- are having to unite as one if they want to have any hope of surviving the End Times.

Incidentally, this makes them the third army based on "mix together formerly separate armies", after Undead Legion and Legions of Chaos.

The leaked data has also mentioned an Elven spin-off force called the Aestyrion, which is based around Tyrion wielding the Widowmaker and becoming the mortal avatar of Khaine, leading a combination of Asur who won't stand to have Malekith as their leader even if Asuryan says he should and Druchii who are so zealous that they feel they serve Khaine more truly by fighting alongside Tyrion. They are a separate force but either die or get annexed into the armies of Eternity King Malekith after the destruction of Ulthuan.