Tengu to Kitsune, Chichi ni Naru

Kuromaikai, a tengu, was once famous as a legendary ayakashi. However, his shrine is now in ruins, and he has fallen so far into decline that even his servants have fled. "It's all humans' fault!" he says, determined to restore his former glory, he descends the mountain and visits an old demon who has made a fortune in the human world. "If you can complete the test, I'll lend you my strength," he is told, and tasked with raising a human baby with his nemesis, the fox demon Miyakineina...!?

(Source: Kodansha, translated)