The Darkness Within (Twisted Thorn) by Ang T. Dalton

Magic is cursed. Fate is a game. And love is the deadliest price. Scarlet Thorne thought she was done playing with the cards she was dealt. But life has thrown her back into the ring. Waking up in Hollow Summit wasn’t all that bad—until she met Fallon, the twin sister she never knew existed. Fallon Fitzroy is everything Scarlet is not: disciplined, calculating, and seemingly determined to hate her. And with their father, General Arrow Fitzroy, Scarlet is forced to navigate not only a fractured family but a destiny she never asked for. To defeat the Grim, the sisters must work with the Wylder brothers. Fallon is forced to ally with her sworn enemy—Shayde—the one she’ll never forgive for the role he played in Scarlet’s capture. Meanwhile, Scarlet has given her heart to Rhodes, even as the curse entwining his fate threatens to tear them apart. Humankind has one last chance to reverse the Mareki’s Curse. And Scarlet and Fallon are the ones bound to fulfill the prophecy… but at a devastating cost. To restore their world’s magic, the Forgotten Realm must fall. And when it does, Scarlet will be forced to give more than her power—she may have to surrender her heart. Read more