From the WCB Art Theme [link] for Scott Pilgrim Girls It is Knives Chau.
Knives Chau (b. March, 1987) is a 17-year-old (18-years-old in Volume 6) Chinese-Canadian high school girl and self-described "Scottaholic" (though she later gets over him). When Knives dates Scott, she is happy-go-lucky, but when he cheated on her (initially "forgetting" to break up with her), her personality drastically changes. After he "grows up" and reveals that he showed an interest in Ramona, he breaks up with Knives and she comes to terms with it. She is one of the seven main characters of the Scott Pilgrim franchise and also the secondary antagonist of the entire series.
Knives Chau was born in 1987, seventeen years before the start of the series of Chinese-Canadian descent. Her life in elementary school is very lonely and her mother nagged her to find someone to fall in love with, as the prospect simply did not interest her. During one such argument on a bus, she met Scott Pilgrim and began dating him. Scott was probably the only thing about her otherwise boring and ordinary life that truly made her happy, and as a result she became obsessed with him. She would occasionally come over to see his band, Sex Bob-omb, play.
Unfortunately for her, Scott broke up with her after he met Ramona Flowers (though he initially "forgot" to break up with her). This outraged her and she cut and dyed her hair and changed her clothing style and becomes bitter, obsessed and jealous. She hopes to win Scott back by becoming more of a hipster. Her discovery that Scott was cheating on her with Ramona causes tension between the two girls, sometimes culminating in actual fights, though later the two reach a level of acceptance of one another.
She starts dating Sex Bob-omb's groupie Young Neil, although she is still hung up on Scott. She and Young Neil later break up, but Knives still hangs out with the group, and by Volume 5 had seemingly developed a mutual attraction to Stephen Stills, however, this was proven to be false at the end of Volume 6 with the realization that Stephen had been dating Joseph.
She used to idolize Envy Adams, based on her success as a musician and her former relationship with Scott but is soon disenchanted when Envy has her drummer Lynette punch Knives hard enough to knock the highlights out of her hair (although even afterward Knives couldn't bring herself to hate Envy's music.) Knives' father becomes aware of Scott's past relationship with his daughter, causing him to hunt him down and try to kill him, though Scott later earns his acceptance.