The Darkest Night by A.D. Starrling

Hana Mae Jin does not believe in magic. Unfortunately, magic believes in her.
When the hospital where Mae Jin works is attacked by terrifying monsters, a power the mortuary assistant never knew she possessed awakens, sending a wave of magic across New York that has unforeseen repercussions.
Nikolai Stanisic has only one wish. To stop his brother Oscar and their father the Sorcerer King from carrying out the dreadful scheme that was put into motion the night they killed his mother. His only chance at success lies in rousing the soul of the being his father fears the most: the rightful Witch Queen, fated to save the world of magic and rule over it.
Thrust into a fantastical realm hidden from mortal eyes, Mae soon learns of her mythical past and the incredible destiny that awaits her. Armed with the weapon and the familiar who were once promised to her, she joins forces with Nikolai and Vlad Vissarion, a seductive Russian mobster who wants to stop a demon-infested gang from taking over the city’s criminal underworld.
With the New York coven and a pair of mysterious magic users from Chicago at their side, Mae, Nikolai, and Vlad find themselves facing an enemy far more vicious than they could ever have imagined and uncover a terrifying plot set in motion by the Sorcerer King and his Dark Council.