Miburo ni Tsubasa

In Kyoto at the end of the Edo period, Shion is a lonely young girl who is a tengu. She is chasing her brother who killed his entire clan, and is attacked by a samurai who has turned into a monster. She is saved by Heisuke Toudou, who was the captain of the Mibu Roshigumi, later the Shinsengumi's 8th unit. In order to stop her brother's ambitions and get revenge, Shion begins living in the human world with Heisuke and his friends.

(Source: Natalie, translated)