Humanborn. Shadows of Eireland, #1

In the war, the mythborn killed her friends, but now humanborn Kaja needs to work with them to uncover a conspiracy or Dublin's streets will run red with blood once more. Less than a decade ago, the Magiclysm, a tear between Earth and another place, brought magic to Ireland-and worse, it brought back the mythborn. The war that followed left Dublin scarred, and cursed Kaja Modrzewska with chaotic magic that will eventually claim her life. Struggling with wartime nightmares, Kaja seeks normalcy amongst the volatile peace working as an information broker when a series of explosions across Dublin threatens to reignite the war.
Both sides are eager to blame the other, so Kaja reluctantly agrees to investigate. But finding the terrorists responsible means working alongside the mythborn's elite killers, and uncomfortable wartime secrets coming to light. Kaja, who had saved a mythborn's life during the war, finds out she has a life debt of her own, and as she juggles her allegiances and obligations, she'll have to decide where her loyalties lie, with her old human allies or the mythborn.