Eldrazor

Eldrazor, the Lord of Blades, is an Elven god obsessed with the skilful arts of war. He seldom ranks high amongst his pantheon, for many Dark Elves scorn his reluctance to fight save in the pursuit of honour. However, once Eldrazor decides to fight, he does so without mercy. Any tactic is permissible within his Arena of Death, and as he constantly redefines the arena's bounds in the mortal ream, it is impossible to know you're within it until it is far too late...

Source

 * Warhammer Armies: Dark Elves 8th Edition -- pg. 45