Ashen Ascendant: Wings of Embers

Elowen and her best friends Yuna Salvadore-Nephilimio and Lyra Salvadore have always known they were different. Born with powers they don’t understand, they hide their abilities from the world. But when they are summoned to Avalis Academy, a hidden school for the gifted, they uncover the truth about their powers and a prophecy that places Elowen at its center. Now, they must face dark forces and decide whether their destiny will save the world…or destroy them.

Cinderbound

She went into the dark for her brother. She came back with a monster inside her. Every midnight, a door to a nightmare world opens and drags people. Iskra wasn't meant to survive it — but the thing that spared her never let her go. The Greywatch hunts things like her. Their best hunter, Dashiel, has been marked to eliminate her. But the more he watches her fight to stay human, the harder it gets to kill her. Also, the monster, Caldris, attached to her..seems to have plans entirely of his own.