it’s kinda confusing but i’ll try and explain the best i can lol.

devils can “die” but ultimately are sent back to hell as the. same devil they were, once they die in hell, they are sent back to earth without any memories of their previous lives either in hell or earth. basically reset.

the death of a fiend is pretty much the same as devil’s death. the only difference is that the corpse the devil is controlling stays on earth while the devil is sent to hell and can return back to earth without any previous life memories.

hybrids on the other hand are special, no matter the reason they whether it be decapitation or any death for that matter, they can always revive when coming into contact w blood. if left untouched and never coming into contact with blood, they will remain dead.