[@Absolis]
Massively OP. It's the most powerful thing he can do. But just doing it once means he's weakened forever afterwards. It's not like other powers, where he's just channeling the energy of the warp. This is like cutting out your liver and turning it into a bomb. He could make maybe three more, but doing so would kill him. And even that one had a permanent toll on his power. The only reason I even brought that thing up is because I wasn't expecting it to be used. I thought 'instant annihilation of the city' was a fairly good deadman's. My plan was for Ruiko to bring it back, and for the Emperor to absorb it once more.

The Chaos Gods are able to influence other universes through the Warp. But if you prefer that it wasn't a Chaos God I'd happily change it, that was just my idea for an explanation. I had no intention of killing your, or everyone else's, characters, so I made something up to save em.

By 40K universe, everything intelligent has a 'soul' or rather a 'presence within the warp'. The physical capability to think and make decisions causes a being to gain a 'soul'. This includes machines. Hell, there was even a robot with psyker powers. Although it usually doesn't happen, as AI is forbidden in the 40K verse. Hence why I stated that any intelligent AI or computer would be annihilated as well. I figured that any remaining security systems would be fairly easy to circumvert, considering everyone is dead and the lizards have all the time in the world.