Ohh yes. Neat. Harvested youkai (though we don't know how many youkai kings behave badly enough for Heaven to go after them, and I got the suggestion that Tenpou's subordinate was killed by a beast) or dead celestials used to make Natakus: sounds likely. If youkai it'd explain why he's itan, if some of Litouten's DNA was added to the mix.

"I convince myself this is love" which I've seen other people remark on also as possibly implying sexual abuse, but that's a whole other tangent).

I think it's beyond an implication myself. Hot-eyed Litouten undressing his son equals what? My mind's in the gutter, retching.