Demon's Darling Daughter is weird because it seems to be about conflating basically the values of contemporary secular satanism with an actual, albeit very manhwa-ish, cosmology of angels and devils. (Specifically, both the angels and the devils are more like factions within a broader and relatively unremarkable medieval fantasy polity.) But also with cute child protagonist vibes. Also some some...unusual gender stuff.
The, like, philosophical underpinnings such as they are, are pretty hit or miss for me, but it does produce some good screencaps.