Maybe a Fake Gintama

Kawaki, who was born in the dragon vein of a planet (Altana), first met Umibozu who was traveling in the universe, and his girlfriend, Kouka. Later, he came to Earth by accident and met the teacher who affected his life — Yoshida Shouyou. He also met a group of friends. The most conspicuous among the group of friends is a fool with silver hair and naturally curly hair, a short man with purple hair, and a little devil whose catchphrase is "Not Zura, it's Katsura!" Gintama Doujin, not transmigration.