Land of No Mortals — N.R. Wick

Seventeen year old Rebecca Ashford and her younger sister, Errol, have finally found safe refuge at Crown Haven, a witch-led survivor colony. Rebecca should be thrilled by the secure place to live and the human contact after spending a year hiding in their family tornado bunker, but ever since her friend, Fox, left she's been plagued by guilt strong enough to mess with her newfound witch powers. When demons destroy Crown Haven, Rebecca uses her power to locate the only person who may know how to fight back. Instead, she discovers that Fox is in danger. She and Errol must rescue him and enlist his help in their quest to learn what caused the demon apocalypse and find a way to take back their world. As Rebecca struggles with her feelings for Fox and with controlling her power, she fights to stay alive and defy the demonic oppressors to protect the people she loves.