The Boy and the Beast (2015)

Nine-year-old Ren has forgotten what it feels like to have someone by his side. The last person who treated him with genuine kindness has been murdered and he doesn't have anything left of his family. With nothing else left for him, he runs into the bewildering streets of Shibuya. He then stumbles into somebody named Kumatetsu, who guides him to Shibuten's beast land.

Kumatetsu to become a candidate once the Lord of the realm retires; but unfortunately, he has no disciples to teach and no way to prove he is worthy of the position.

While the two have different goals in mind, they become closer with each other to the point of helping out one another in many other ways than what they expected.