Nadia: Mistress of the Undead - The Sebastian Chronicles

Mistress Nadia wasn't born into the lifestyle, she earned the title. Being a dominatrix became her preferred method of coping, a way to reclaim her life. Never would she suffer at the hands of another. Nadia's life began as any peasant youths had in the rural Russ lands of the fourteenth century, an area later known as Russia. She was born the second of three daughters in a tiny farming village, but it was the summer of her eighteenth birth year when life as she knew it forever changed.
Through centuries of extensive training, she worked past the nightmares and PTSD. This newfound way to release the demons of her traumatic past, but at the same time use her gifts to help those in need, was what she craved. What she lived for. Some had lost their way and merely needed guidance, while others required a firmer hand. Through her unconventional methods, Mistress Nadia was able to help them all.
This is Nadia's story from novelette 4, Prohibitions Inhibitions, in The Sebastian Chronicles.