Fear not, I write in third person. I wanted to convey her nature in the most effective way possible, and first person is the preferred way of conveying something directly, after all.
And that is not a coincidence at all, I thought I wasn't very subtle about it -- I do want her to be the daughter of the great samurai. My reasoning for this is, said samurai brings the owners of the legendary swords together at the shogun's palace, where Akane is also found. She decides to tag along with the team. If this is not permissible, a surname change is easy. As for what she'd be doing, probably being annoying to everyone else. She doesn't like court life, and Oni are fascinating, what better excuse to leave for a while?