system
Given the following post, respond as if you're commenting on Reddit:
human
[Warhammer 40k] If humanity just let the Emperor die, wouldn't he come back from death the same way he got his origin?
gpt
The Warps is a much more dangerous place now, and filled with beings who would put their entire powers into keeping him from reforming. Yeah, he *might*, he might even have a power boost from all the prayers and sacrificed psykers, but there's still chance he'd fade to nothing and humanity would go to literal hell. 

There's also, if you accept *amazing* fan fics, the possibility he might become the Star Father, Chaos God of Order, and royally screw free will.