A Fury Of Shadows by A.D. Starrling

They stole someone precious from her. And she will do everything to get him back.

After losing Nikolai Stanisic to the Sorcerer King and his Dark Council in a brutal attack that left her battered and broken, Mae Jin resolves to rescue the man who’s come to mean so much to her. But just when she’s unravelling a new form of magic that could help Nikolai recover his memories, Mae and her friends come under attack from Oscar Beneventi and a new breed of devils led by Barquiel.
The unexpected allies that come to their aid bring with them a perturbing development. Dietrich Farago, the Immortal long affiliated with Barquiel, is not only modifying devils, he has helped the Sorcerer King devise a way to control Mae.
Meanwhile, Nikolai Stanisic slowly adapts to his new life in the Dark Council and the horrid reality of having been a puppet under the Witch Queen’s powerful illusion. Bent on proving his worth and his loyalty, he places his powers at his father’s disposal to help him find and unlock the elusive Book of Shadows.
Time is ticking and the Sorcerer King is drawing closer to achieving his goals. Can Mae and her friends rescue Nikolai and foil his father’s evil plans, as well as those of the treacherous demon who serves him?