Abaddon.
Okay so, I have an opinion, I don't know if there's anyone else here who thinks the same as me:
It bothers me a little that, in season 2 episode 4 where Abaddon acts more like a child with Kathy, many ppl say "It's the Vessel, the Vessel came out a bit more that day!"
It's like OK yeah, it's a nice theory ig because, their souls did end up tied in the ritual, but sometimes I feel like it's a very simplistic and black-and-white toned way to see Abaddon. Why can't Abaddon have a cap acting dumber and more childish n kind than normal without anyone saying "It's the Vessel"?, I mean, he has his own personality too, sir. ✌
Besides, I find it more fun that Abaddon is like, very adult and very child at the same time, he's immature most of the time and that's what's cool because he's so silly, I also find it annoying that a big part of the fandom treat him completely like a small child, btw the baby is billions of years old bro. 😭🙏
But idk, I prefer the thought that in this season, Abaddon acted more childish because he was more confident or felt more comfortable with the Freelings.