Why defeat him, when you can have him locked away in the Warp, having him slaughter endless Daemons - They are eternal anyway? This way he makes absolutely ZERO difference, as opposed to being dead where he could become a martyr.
Seems to me like they want him to think that he's immortal, yet trapped; A much greater punishment and mockery than just killing him.
Seems to me like they want him to think that he's immortal, yet trapped; A much greater punishment and mockery than just killing him.