Heir to Sin — Vladimir Duran

Even in a city flying beyond the clouds, one as alien as it is beautiful, some things never change. Fathers are indulgent of their daughters while mothers take them to task. Except most families aren't in a silent fight for survival against a ruthless and deadly enemy. Come meet Olga's family, the bloody shard of glass imbedded in her clenched fist.

Excerpt

Keeping her breath even Olga pushed herself for more speed. Her waifish body was a nude blur as she moved through the memorized forms of the serpent style of Trakan. Hair tied back in a neat horse tail her blue eyes were razor focused. The heir of Novakatana's movements were sinuous, relying on sudden burst of speed for striking power. She liked the style, it fit what she thought a fight should be. Quick and decisive.

The sweat streaking her body, the tiny twinges in her limbs when she went for a difficult form, the small mistakes she made. All of it spoke of Olga not using her Knight state. If she was ever going to get good she needed to do it without aide.

Stealing the instructional book for this form had not been easy. Anything having to do with the Harrowers was prescribed reading. Vlad's friend, the ambassador, probably had a full set of twelve lying around, but she and Jack had agreed not to go there unless they had to. Being able to sell illicit books was one of the major privileges of the ambassadorship. But Wraith had to respect them if he was going to teach them.

And he would teach them. Vlad was her way, her only way of getting better at the thing that defined Knights. Combat. The only way that did not involve running away to Safe Haven or reveling herself by trying to hunt demons. He knew things about combat they didn't put in books. Things about Knight combat that had never been in a book.