unknowable

Michael Demiurgos Death could never match Lucifer's great power, so she couldn't claim him who wouldn't allow himself to die under any dangerous circumstances. And the strongest archangel Michael whose power comparable that of his brother Lucifer, never refused his own end but accepted it gracefully, so Death could claim him. But, if she pissed him off and he complained her endless embrace… Her existence would wipe out just as easily by Michael's Demiurgic power.

Mother Night & Father Time Death of the Endless is embodiment of end, but her parents ignored end of everything.
And Night is without end and boundary, Time is manifestation of time itself which is necessary for Death to exist.