Hailed By Fiends by Eva Chase

How many monsters does it take to stop the greatest villain of all?
I’ve let myself become more of a monster than I ever wanted to. Now the shadowkind are flocking to my side, eager to stand with me.
But I don’t know if I’m strong enough to foil to the villain who’s put the whole world in his vicious sights. This borrowed heart might have given me my powers, but using them has rushed me toward my inevitable end.
I hate having to drag anyone else into this horrible battle with me… but if I can’t find a way to build up my new army—and fast—the world as we know it will disappear.