Japanese anime seems dominated by overstylized action flicks populated by squeaky-voiced kids whose ability to rain down death and destruction belies their babyish features.

Not so the work of Mamoru Hosoda. Best known in America for Summer Wars (2009) and Wolf Children (2012), Hosoda crafts sublimely beautiful coming-of-age stories. The kids in his movies may start out petulant, irresponsible, and selfish, but invariably they grow up.

The Boy and the Beast, the director's latest coming-of-age story, is a brilliant, funny morality tale that examines the transformative effects of martial-arts training.

It tells the life story of Ren, a 9-year-old runaway so deeply wounded by the death of his mother that he has decided to hate humanity.

One day, he finds himself in an alleyway that leads to a city populated by strange, anthropomorphic "beasts," as the English subtitles put it. (The Japanese word, bakemono, translates as "monster" or "goblin.")

Hosoda upends the usual take on humans and monsters, making the beasts the more refined, moral beings. They revile humans as savage creatures.

"Humans are weaker," one beast tells the human child, "and harbor darkness in their souls."

Ren finds himself in the middle of a rivalry between two martial-arts masters vying to become the next lord of the city. Iozen, the favorite, is a refined, skilled swordsman and beloved hero who has dozens of disciples.

Ren is drawn to the underdog Kumatetsu, an immature hothead who dominates opponents by brute force. An orphan who taught himself to fight, this master has no time for anyone else - and no followers. The current lord, a wily, rabbitlike guru, demands that Kumatetsu show he can train a single apprentice before he can fight Iozen for the title.

And so begins a long, rocky relationship between boy and warrior, full of comic banter. Equally stubborn, equally wounded by a hard life, and both full of rage, they butt heads again and again.

The Boy and the Beast follows Ren's progress for nearly a decade, eventually taking him back to the human world and back again to the world of the beasts as he battles the rage within.

Even with a running time of 119 minutes, The Boy and the World tries to do far too much. Its narrative range, rich themes, and moral depth would have been better broken into two or more films.

Still, it's a fitting addition to Hosoda's remarkable body of work.