Zealark is for certain a very interesting case and certainly an anomaly. Demons in here are kind of similar to Frieren where they take pleasure in killing them and destroying settlements for the Demon King. Though I don't know where the similarities end, I get the feeling that if demons (like
) are striving to understand humans, then Zealark's method could provide some sort of meaning, seeing as he basically is reliving life and questioning it over a century.
(Or maybe not and I'm just blowing gibberish out because it would probably take a lot longer and like Frieren said, humanity would be wiped out before it)