Dealing with the Devil — Jennifer Siddoway

Wynn Hendricks is not your average teenager. All she wants is to finish high school, but normal things seem impossible when the monsters under her bed are real… Unexpectedly, a Demon Lord appears, declaring her soul is his property and throwing her world into utter chaos. Heaven and Hell are at war, with her fragile life caught between them. To regain her freedom, she must conquer the Seven Deadly Sins and prove she has the strength to control her inner demons. Wynn discovers new forces, new allies, and enemies she never knew existed -- including her own human weakness. She refuses to go down without a struggle, and against the powers of darkness, she vows to Fight. Like. HELL.