During 1999’s No Man's Land event, Cassandra Cain was given the mantle of Batgirl by Barbara Gordon (then acting as Oracle after her paralysis by the Joker). As the new Batgirl, Cassandra was brought into the fold of the Batman Family and taught to work as a superhero on a team under the supervision of Batman and Oracle. Under Barbara's care, and with some telepathic doctoring, Cassandra's brain was made capable of understanding and producing speech, though her communication skills remained limited at best.
After she proved herself by fighting a metahuman, Batman allowed Cassandra to face off against some of the more prominent Super-Villains in Gotham City.
Over time, Cassandra's past surfaced, as her father worked to track her down. David attempted to destroy Cassandra's relationship with Batman by sending him footage of her as a child, killing a man. But the plan backfired and made Batman even more certain he’d made the right choice in helping to rehabilitate her. Eventually, Cassandra learned her mother was Lady Shiva, one of the deadliest assassins in the world. Shiva herself came to Gotham to offer her daughter further training, under one stipulation: twelve months later, Shiva and Cassandra would fight to the death.
When the day came, Cassandra won, becoming one of the only fighters to beat Lady Shiva in combat. But she spared her mother's life, prompting Lady Shiva to swear vengeance on her daughter the next time they met (BATGIRL #25, 2002).
One Year Later and Black Bat (2006-2011)
One year after 2006’s Infinite Crisis, Cassandra was revealed to have abandoned her alter ego as Batgirl to work as a Super-Villain and leader of the League of Assassins. Distraught, confused and betrayed by her apparent change of heart, Tim Drake made an attempt to free her from the League's control, only to find himself engaged in a fight to the death with Cassandra.
In her new villainous alter ego, Cassandra joined the Titans East under the leadership of Deathstroke, where she faced off against Tim during an attack on the Teen Titans. It was eventually determined that Cassandra's turn toward evil was the result of Deathstroke’s manipulation.
Once free of Deathstroke's mind control, Cassandra felt lost and disillusioned with her path in life. She resolved to hunt down both Deathstroke and her father to make them pay for what they’d done to her. But in doing so she found herself at odds with the rest of the Batman Family (BATGIRL vol. 2, 2008). Bruce was able to dissuade her, and officially adopted Cassandra as his daughter shortly thereafter. She began working as Batgirl alongside Batman and the Outsiders until Bruce's apparent death in 2008’s Final Crisis.
With the Outsiders leaderless and Batman gone, Cassandra sought to reinvent herself. She passed the mantle of Batgirl down to Stephanie Brown and—following Bruce Wayne's return —joined Batman, Inc. in an all new alter ego: Black Bat. With Batman, Inc., Cassandra acted as a Super Hero internationally, basing herself in Hong Kong.
The New 52 (2011-2016)
Following 2011’s Flashpoint, Cassandra was given an all-new origin and alter ego. Her father, David, was reinvented as a vigilante named Orphan, who worked under a Super-Villain and cultist named Mother, intent on building the perfect child soldiers. David, however, sought to impress Mother and secretly hid Cassandra away, where he taught her to "read" bodies in motion like open books, but never to speak or communicate. Under David's training, Cassandra became a relentlessly efficient fighting machine. When it came time to reveal her to Mother, David did not receive the praise he believed he deserved. Instead, Mother rejected Cassandra as an abomination and punished David for his insolence in going behind her back.
David later sacrificed himself to kill Mother and end her abusive regime. Cassandra came to understand the horror of what had been done to her and turned toward the Batman Family for redemption. She took the code name Orphan after her late father (BATMAN & ROBIN: ETERNAL, 2016).
Following 2016’s DC UNIVERSE: REBIRTH #1, Cassandra joined the Gotham City vigilante team, comprised of Red Robin, Spoiler, Clayface, Batman and Batwoman. She has slowly gained the ability to communicate using a combination of signed and spoken language.