Almost Eternal - updated 11th August

You're not weird. Everything you say is totally valid. If I was a reader, at this point in the story, my opinion of Seth would be most similar to yours.

I'm biased in favor of Lilith, but from what I can tell, Lilith is actively trying to preserve lives. Caleb can’t control himself well, but seems to be trying, at least now. But Seth? He doesn’t want to control himself. From what I can tell, he likes being a monster. He doesn’t seem to care about people's lives at all. The fact that he’s desperately attractive and charismatic doesn’t make it better for me. It makes it worse

Correct, he doesn't try to restrain himself in any way whatsoever. He is the epitome of what we have learned of rogues. And it would appear that he likes being a monster... I'll stop now I'm walking the spoiler line.