A korean barmaid that Ken encounters after meeting Tae-Soo. She later becomes the reason why Ken and the Sun-Ken Rock Group take over the red light district.
In the beginning she was just a barmaid the gang used as a hangout. She later got deeper involed in the story when Ken protects her from getting raped by a few gang members. Sadly she is betrayed by the owner of the tea shop and taken hostage. She is beat, whipped, and tortured in other ways.
After the training arc Ken runs into miss yoo in a brothel she informs him that after he left her in her village. The yakuza come and raped her until she forgot she was human. They posted pictures of it and her parents committed sucidie. It is because of Miss Yoo that Ken decides to take over the whole red light district and to destroy the entire garugi gang.
Miss Yoo appears to have deep feelings for Ken, but cant act upon them since she is too weak to follow Ken. Miss yoo is a loyal supporter of Ken and will never betray him.
She is the current boss of the Red Light District, she was given the postion from Ken and is very thankful for everything he has done for her. Since then she has only appeared once but it was a very quick appearance telling the guys she's working at a "kiss club".