Grace Rosa

Grace Rosa is an assassin, driven by a single thing: discovering the secret of her adoptive father's disappearance. He trained her to become a lethal killing machine, able to wield any weapon she can get her hands on, before inducting her into the ranks of the shadowy organisation known as Alterna. But could the very people she serves as a hired gun have something to do with him vanishing? And to what lengths will she go to enact her vengeance on the people who have wronged her?

(Source: Titan Manga)