Yu Yu Hakusho (1992)

S04E02 Three Strangers, Three Kings

While the three unfamiliar visitors in Kuroko's home share their purpose, Yusuke starts to feel that something isn't right. These demons have come to deliver a crucial message: his ancestor is a king in the Demon World! They warn Yusuke that if he doesn't journey to the Demon World soon, the balance of power may be disrupted, potentially threatening humanity's dominance at the top of the hierarchy.