Tsubasa is the next heir of the Tsubame Tenryu Ryouge, a martial arts school threatening to collapse due to lack of funds, and was originally hired by Sakinomiya Ukyou to assassinate Yoichi.
She is a clumsy and shy girl, who dreams of having a normal life. She has a crush on Washizu, because he was the first one who treated her normally. But she gets hurt deeply after hearing Washizu saying that he hates martial arts.
She insisted to her subordinate Angela that she should go to the same school as Yoichi so she would have a good opportunity to assassinate him, although her true motive was to be a normal high school girl. In one incident, she slices a soccer ball heading towards her in front of her classmates due to her instincts and gets depressed because everyone became silent. Yoichi openly greets her to ease the tension of the scene, and everyone else follows suit. After school, Angela ripped Tsubasa's clothes off in public. She turned into a deadly martial artist in a trace-like state due to her embarrassment. She attacks Yoichi at Angela's orders. However, when Washizu interrupted their fight, Tsubasa broke out of her trance and fled the scene crying from humiliation. Later, she told Angela that she hates both martial arts and Angela. But the next day, she forgave Angela and started a ramen shop with her.
Source: Wikipedia