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!”