Diamond City by Francesca Flores

Good things don’t happen to girls who come from nothing…unless they risk everything.

Fierce and ambitious, Aina Solís as sharp as her blade and as mysterious as the blood magic she protects. After the murder of her parents, Aina takes a job as an assassin to survive and finds a new family in those like her: the unwanted and forgotten.
Her boss is brutal and cold, with a questionable sense of morality, but he provides a place for people with nowhere else to go. And makes sure they stay there.

DIAMOND CITY: built by magic, ruled by tyrants, and in desperate need of saving. It is a world full of dark forces and hidden agendas, old rivalries and lethal new enemies.
To claim a future for herself in a world that doesn’t want her to survive, Aina will have to win a game of murder and conspiracy—and risk losing everything.