Hex

Hex, a character in "The Crown and the Flame" series, is the new weapons master for the Nevrakis Family. She's got her first appearance in book 1, chapter 11.

Look
Hex has short black spiky hair and bright blue eyes.

Whitlock
Hex was Whitlock's mentor. He seems to be the only one Hex cares about because she doesn't want him notice her committing crimes. Whitlock respected Hex very much and is very disappointed about what she turned into.