Maybe the collective counsciousness of all the Exarchs that wore the armor before and who's souls became one with it upon their death?
Or a Demon attracted by too many teleportations through the warp?
Or maybe even a Phoenix King?
Or his supressed dark personality traits that try to turn him into a Dark Eldar.
So many possibilities.
Nice drawing there :D
Really good looking, and I would enjoy reading a comic in it.
But for me it does not capture EataTaus feeling as I have come to enjoy it.
But for this dreamworld, keep it going.