Sin was introduced to Black Canary when Canary made a deal with Lady Shiva. They would switch lives for a year, in which Dinah would train as Lady Shiva had done, while Shiva herself took her position with Oracle and the Birds of Prey. During Dinah's training, she arrived at a village in Asia, which was ruled by a martial arts master known simply as Mother. Dinah was allowed to be trained by the cruel matriarch, though it often came as horrible mental and physical abuse.
While there, Dinah met a little girl dubbed Sin. Sin was being groomed to become the next Lady Shiva, following the death of the current one. Sin and Dinah developed an immediate relationship that bordered on sisterly or mother/daughter. When Dinah grew tired of Mother and her training, she decided to leave, and took Sin with her. Mother attempted to stop her, but was no match for Black Canary.
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 however, Dinah slowly 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 decided to leave the team so as to raise Sin full-time. This would prove difficult however, after Dinah once again joined the Justice League.
Later, the League of Assassins attempted to kidnap Sin, seeing the martial arts prodigy as a messiah that could unite their splintered and then leaderless group. In an attempt to save Sin from the League, Green Arrow faked the child's death. Though the decision pained him, he concealed the truth from Dinah so that her grief would be real and convincing to their enemies. Dinah later learned of her foster daughter's survival.
Currently, Sin lives in a secluded monastery, being kept 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.
Despite her youth, Sin is an expertly trained martial artist and can hold her own against most enemy combatants. She is also quite skillful at playing the Pokemon trading card game. 
Sin possesses the strength level of a child her age, size and weight who engages in intensive regular exercise.
- The name "Sin" may have been created to dehumanize Sin. While training, Dinah was given the name "Tag", meaning swine.
- 15 Appearances of Sin (New Earth)
- 6 Images featuring Sin (New Earth)
- Quotations by or about Sin (New Earth)
- Character Gallery: Sin (New Earth)