Cassandra Cain was raised as an assassin. Growing up, her father never taught her to read or write, only to fight. She grew up knowing only one language - body language. Her mind processes human motions as fluently as ordinary people speak their native tongue. She can see moves before they happen or read a person's intentions simply by following their movement patterns. She was an experiment to create the ultimate human fighting machine. At the age of eight, she made her first kill. Then she ran away. She wound up in Gotham, under the tutelage of the Dark Knight. She has become Batgirl.
I read through the current 70 issues over the weekend. It's pretty good. Batgirl almost always faces up against normal people - goons, thugs, mafia and whatnot. She's not metahuman either, but her superior abilities allow her to dodge bullets and kill with her bare hands (Not that she does kill mind you, but she CAN.) The fact that she's illiterate and basically ignorant of how to interact with the rest of society makes the comic all the more interesting and provides a lot of room for her to grow as a character.
The only thing I don't like about trying to follow a single comic series - crossovers. You read an issue, and suddenly there's several other comics you need to read to get the whole picture. I can see why they do it.