Bet that Spica is half succubus/half human and he can actually live in both worlds.

I think he is actually an angel, I see some raws and it seems so

Spoiler alert

Well, I'm might be wrong too, bcs its in japanesee, and I can't read it

Oh ok

can you share the raw link pls?

You can look at the last page of chapter 05 there's a link there, I used the japanesse raw link, but I read the short version bcs you have to pay to see the full version tho. Oh, If you read there, it started at ch. 05, bcs ch. 05 here is ch. 04 in the raws