She approaches her life with a optimistic yet reflective attitude, unafraid of what others think of her. She is also incredibly hardworking as well as dedicated. It's easy for her to make friends with anyone no matter what.
Why not be?
She shares her birthday with K-On's Yui Hirasawa, as well as the each kanji in her name corresponding to one of the 4 main K-On cast.
The "scar" on her leg is just a tattoo. It's probably even temporary, as it switches legs between anime & game. Or the animators just didn't care.