The Romanov Oracle by Molly Tullis

When the Romanov Empire was dismantled in flame and firing squad, one name rose to heights above all the rest: Anastasia. During the final years of her family’s rule, the near omnipresence of one charlatan drove rumors to a feverish height. Rasputin.
But what if the magic wasn’t his… but hers?
Anastasia Romanova carried Romanov blood, full of magic, once depleted and diminished throughout her family tree over the years. But when it shows up in her as strong as her ancestors, an incident in her childhood forces her family to attempt to drain the magic out of her. The burden grows as her powers become too strong to control, leading Anastasia to try and fight fire with fire… but there’s always a price for magic.
The enigmatic servant boy who was witness to her very first spell is forced by her family’s advisors to assume the priesthood. He becomes the scapegoat for Anastasia’s magic, taking on the moniker Rasputin.
There’s only one thing the dvoryanstvo and her family never expected. The magic is real and so is the relationship between Rasputin and Anastasia, who are determined to see her powers unleashed. Even if that means everything else burns.