Once upon a time, the gods made a trinity. Every five years, a trio would reincarnate: 

A Dark Lord to threaten the land,
A Princess to wield the powers of light,
And a Hero to seal away the darkness...

...Except things didn't quite go right this time.

The current incarnation of the Hero (his name is Akuji) is depressed. He's a sad, wholesome little bean that you'd probably end up hugging. He can be powerful, but said power is buried under a lot of depression and doubt.