リョウ・サカザキ

An instructor at the local dojo.
He saved the protagonist from a guy who was hitting on her in middle school and she's been coming to the dojo for lessons ever since.
Watching Ryou working hard teaching karate despite his financial difficulties can be encouraging, but he really just doesn't realize the trouble he's in.
But he has a rich father and younger sister and rich friends to support the dojo.