When a god dies, its powers are transferred to its killer(s).
When a god is bloodied they will discorporate, leaving their bodies and existing as a weakened essence, returning to their normal state in a year. Gods can only truly be killed under certain circumstances specific to each god
Demons and Devils slain on the material plane return to the abyss or hell respectively. Demons and Devils can only be truly slain in the abyss or hell respectively