A girl from Baki's school, her mother is Baki's landlord. Her father fought and died in the Underground arena. She cares deeply for Baki, but denies when asked. She is disillusioned by Baki's violent life as an Underground fighter and begs him several times to quit. Though she still disapproves, Kozue better understands Baki's resolve after visiting Emi's grave site. After Baki's first tournament match, he reveals that he cares for Kozue.<br /><br />
