This is Reyna.
Her family hunts vampires (they'll take most non-human evil creature cases, but they specialize in vampire-killing). They are one of the most well-known hunter organizations on the planet.
At the age of 15, Reyna ran away from home. She returned three years later with a one year-old son named Tomas, and has to this day never explained to anyone where she was, what she did, who the child's father is, or even if it is biologically hers at all (though her attitude towards him is unmistakably maternal, and she takes excellent care of him). Upon her return, she immediately began working in the family business, and is now (at age 21) rapidly approaching the ranks of the best vampire hunters in the world.
She has one younger brother, Jack (currently 17) who is her best friend (but who knows no more about her whereabouts between the ages of 15 and 18 than anyone else in the family). She does have a sense of humor, but it's very dark and rarely seen. Reyna sometimes gives the impression that she enjoys the killing aspect of her chosen career just a little too much.
She could probably kick your ass without trying too hard.
Quickie sketch, sloppily colored with a mouse in Photoshop.