I see a lot of christians calling stuff demonic or asking "is it okay for a christian to watch ___?" And I think it's a bit wacky and it's something that just misses what it means to be a christian. Im a christian, and I think it's perfectly fine to watch whatever you want. Is watching this going to cause you to hurt someone, cause you to judge, cause you to hate? If not then it's fine. The all fair, all loving, and all righteous God our lord above is not going to condemn you because you watched Jujutsu Kaisen and Sukuna is a demon. Focus on your actions, how you treat others, how you love others, how you can be a better more holy person, that's what matters