7. Cassandra Cain
The daughter of David Cain (an assassin) and Lady Shiva, Cassandra Cain was raised as an expert killer. Instead of being taught how to communicate, Cain was raised without fostering any close relationships and only knew how to fight. Her first known kill was at the age of eight years old, when she killed a businessman while her father secretly recorded her.
Eventually, Cain turned to the light side and joined the Bat-universe as Batgirl during the No Man’s Land story arc. The first Batgirl to have her own comic series, Cain is such a sharp fighter that Batman has even acknowledged she may be able to overpower him. Even though she still has trouble communicating, she uses her insane fighting skills for good, choosing not to kill as she tries to walk away from the dark legacy of her parents.