He looks like a bad-tempered little chubby guy, with a plump appearance but a big belly full of weird ideas. He has two ears like a little fox on his head, and a plump, fluffy, and extremely naughty tail on his butt. He was obviously just a little monster, but he boasted that he was an immortal master who had fallen into the mortal world. He said that sooner or later he would return to the fairy world, but he had to wait for a girl in the mortal world for three lives.
He abides by the contract and grows up with the girl. She has grown up to be a beautiful woman, and he is no longer the childish little monster he was before. He said that he was just a little demon, not a fairy, and he didn't need to go back to the fairy world and could always stay with her.
However, she would never have thought that a lie would lead to a farewell...