Bakemono no Ko

After his mother's death, nine-year-old Ren runs away from relatives who barely understand him and disappears into the streets of Shibuya. There he follows the rough beast Kumatetsu through a hidden passage into Shibuten, a realm inhabited by beasts, and is taken in as the warrior's reluctant apprentice under the new name Kyuuta.

Kumatetsu needs a disciple to prove himself worthy of succeeding Shibuten's lord, while Kyuuta desperately needs somewhere to belong. Their tempers clash for years, yet teacher and student slowly become the family neither expected. As Kyuuta grows and rediscovers the human world, he must reconcile the two lives inside him before loneliness and anger create a danger that threatens both realms.