No but I agree very much
So far of what I have shown of his backstory, Error was only thrown out of the angel castle and lost his status as an angel. He is not a demon yet but instead he is now stuck in the mortal realm. Feeling alone and confused what to do.
To be able to transform he needs to behave like a demon and ignore all the rules and morals he had learned when he was an angel.
When he now does something “bad” his body slowly transforms until he is a full demon.
His transformation as well as another important event, are what my next video is about so I don’t want to spoil too much!~
To why Error was thrown out in the first place, I can remember answering an ask a while ago where I explained it in more detail :3