Nura

A supernatural saga of a 13-year-old by day, and a leader of a demon clan by night-straight from the pages of Weekly Shonen Jump!

While the day belongs to humans, the night belongs to yokai,
supernatural creatures that thrive on human fear. Caught between these
worlds is Rikuo Nura. He's three-quarters human, but his grandfather is
none other than Nurarihyon, the supreme commander of the Nura clan, a
powerful yokai consortium. So, Rikuo is an ordinary teenager three
quarters of the time, until his yokai blood awakens. Then Rikuo
transforms into the future leader of the Nura clan, leading a hundred
demons.

Rikuo takes action to cement himself as the Third Heir to the Nura clan as Nurarihyon prepares to officially hand the mantle of power over to him. The political move will change the landscape of the yokai power structure, and could grant Rikuo's friends higher positions than they ever dreamed! But new responsibility brings new problems and breeds new discontent.