"Batgirl: Queen of the Assassins" from Batgirl vol.1 #68 (DC, 2005) by Andersen Gabrych, Pop Mhan and Jesse Delperdang
You know, it's strange and sad to me that the first Batgirl to get her own ongoing series wasn't Barbara Gordon. Prior to 2000, the original Batgirl had headlined two measly Specials (one of them from the animated universe). The Batgirl blessed with a 73-issue run is instead Cassandra Cain, whom Wikipedia describes as "the daughter of assassins David Cain and Lady Shiva, she is trained from early childhood to read human body language instead of developing verbal and written communication skills as part of her father's conditioning to mold her into the world's deadliest assassin. However, after committing her first murder, she vows to never again use her martial arts prowess to kill." Like Azrael, she is a member of a visible minority (in her case, Asian), so they make her wear a full-face mask. Seriously, WHAT IS UP WITH THAT?!
Anyway, I never read this Batgirl. Part of it is timing (I was concentrating on repaying my student loans at the time), part of it is a character that seemed dark and violent and I'd had enough of that. Reading about her now, the mute/dyslexic element looks intriguing, though like another Batgirl I know, she's lost her disability. She can now be seen occasionally in Batman Inc. as Blackbat.