The War of Odds by Linell Jeppsen
Sixteen-year-old Sara Giddings is a lost and lonely girl after the death of her mother, and like many young people forced to deal with life’s tragedies, Sara begins to dabble in drugs and alcohol.
All of that changes when her father takes her to the tiny community of Ashbrook, which overlaps the land of the fae. Here, a young sprite named Pollo discovers that Sara is not a typical teenager, but a witch with immense, untapped power- the power to heal.
Pollo, a cat named Hissaphat, and the wood nymph, Muriel convince Sara that her powers may be the only key to healing what ails the fae, and Timaron, king of the Unseelie court.
Soon, Sara and her two friends, Nate and Chloe, are thrust into a dark and deadly world as they endeavor to free Timaron, whose mind has been possessed by demons and who, in his madness, has declared war on humankind.
With only her two friends and a band of magical misfits, Sara must travel across a dying world. Hunted and haunted by forces even the faeries fear, Sara must reach Unseelie and face the prince of darkness himself, wielding a power she barely understands, to save the faerie king and the fate of two worlds.