This thread is to celebrate the glorious character that is Cassandra Cain, the one true Batgirl.
Batman and the Oracle gifted Cassie with the Batgirl costume after she gained their respect by saving the life of Commissioner Gordon. Even after Batman learned about her sordid past, he continued to value and respect her.
From birth, Cassie was trained to be an assassin by her father. She was not taught to read or write; instead, reading body language was her only language. She was able to read people's movements and predict what they were going to do. Upon taking the mantle of Batgirl, she was trained further by Batman, Oracle, Black Canary, and Lady Shiva.
Here is Cassandra paying her father back with death: