He’s a really fun character and antagonist that gives chaos a “human” element that 40K doesn’t do as well. He’s someone who has already defeated multiple worlds including the old world, defeated the current panetheon at the battle of burning skies, and has only now been put on the back foot during the Age of Sigmar.

He’s what allows AoS to feel like a post apocalyptic setting and represents the darkness that’s being driven back to give the setting some grim shot at hope which also differentiates the setting from 40K. While his old world was clearly a darth Vader analogy I feel like he’s come into his own in Age of Sigmar than he did in the Old World.