Talk:Mamono/@comment-168.103.235.155-20141129071019/@comment-12776-20141129073211

If you want actual proof. Then no. Thing is, much of the info come from in-universe perspective, and the narrator has very limit experience to their lifetime.

But if you want just an implication, then it's stated in Deruella's profile. "a high rank monster with a lifespan that can even be said to be infinite" (and this profile is actually The Order's report).

That being said, I'm pretty sure while they, as well as gods, can have infinite lifespan, they can be killed.