Sin is a character appearing in books published by DC Comics. She first appeared in Birds of Prey #92 (May 2006), and was created by writer Gail Simone and artist Paulo Siqueira.
Sin was introduced when Black Canary made a deal with Lady Shiva to switch lives for a year, in which Dinah would train as Shiva had done, while Shiva took her position with Oracle and the Birds of Prey. During Dinah's training, she trained in Asia under "Mother", a cruel martial arts master and matriarch. While there, Dinah met a little girl dubbed Sin who was being groomed to become the next Lady Shiva, following the death of the current one. Sin and Dinah developed an immediate familial bond. When Dinah grew tired of Mother and her training, she decided to leave, taking Sin with her.
Returning to Metropolis with Sin, Dinah introduced Sin to her friends in the Birds of Prey, who all took a shine to the girl. They began to teach her the wonders of the western world and educate her in English and name-calling (she on occasion addressed Helena as "Spinster"). Over time Dinah began to question her life as member of the Birds of Prey, now that she had a child to care for. After several missions, she leaves the team to raise Sin full-time. This would prove difficult after Dinah rejoined the Justice League.
In the Black Canary miniseries, the League of Assassins attempts to kidnap Sin, seeing the martial arts prodigy as a messiah who could unite their splintered and then-leaderless group. In an attempt to save Sin from the League, Green Arrow fakes the child's death. Though the decision pains him, he conceals the truth from Dinah so that her grief will be real and convincing to their enemies. Dinah later learns of her foster daughter's survival.
Sin lives in a secluded monastery, to keep her safe from the League of Assassins and others who would exploit her intuitive gift for the martial arts. Black Canary makes occasional trips to visit her, still playing the role of mother part-time.
