18 years ago - Cassandra Cain is born, the daughter of David Cain and Sandra Wu-san. She is part of experiment by David Cain to create the perfect assassin, the League of Assassin's fabled "one who is all". She is brought up without language.
3 years ago - 15-year-old Cassandra Cain runs away after committing her first kill. She finds her way to Gotham during the No Man's Land quake, where she stops Victor Zsasz from killing Alfred Pennyworth. Her father David Cain battles Bruce Wayne to get her back, but retreats after she says her first work, "stop". She quickly adopts the role of Batgirl, accepting training from Barbara Gordon.
2 years ago - 16-year-old Cassandra is first confronted by Sandra Wu-san. She is told that they will battle to the death. When they meet again Cassandra defeats and spares her, and discovers that she is her mother. She defeats her father David Cain while he is framing Bruce Wayne for murder, leading him to turn himself in.
1 year ago - 17-year-old Cassandra Cain leaves Gotham for Bludhaven to assist Dick Grayson. She is given Katana's sword, and takes on her new Silhouette identity.
now - 18-year-old Cassandra Cain agrees to pass on the Batgirl identity to Stephanie Brown, and to help Barbara Gordon train her. She becomes a part-time member of the Birds of Prey.
Cassandra was awesome. The very first Batgirl to headline her own ongoing series and a completely original character, she starred in her own comic for over a decade before she was unceremoniously wiped from continuity.
Her story is fantastic, and there's very little we need to do to change it, but we did alter some elements later on. In the comics, she becomes a part of the Batman incorporated arc, taking up the name Black Bat, operating out of Hong Kong. It's a decent idea for the next step in her journey, but we like the character too much to pack her off to the other side of the world. Instead, we had he move to Bludhaven. At a time when Dick Grayson is leading the Titans offworld and then leading a new Watchtower, she would be an invaluable asset in his protection of his city. We also altered her name to something a little more deliberately ninja-ish, and gave her the enchanted sword of Katana. the end result is a character more in keeping with the original concept for Cassandra.