Dark World Series by Cara Lynn Shultz

Paige Kelly is used to weird--in fact, she probably corners the market on weird, considering that her best friend, Dottie, has been dead since the 1950s. But when a fire demon attacks Paige in detention, she has to admit that things have gotten out of her league. Luckily, the cute new boy in school, Logan Bradley, is a practiced demon slayer-and he isn't fazed by Paige's propensity to chat with the dead... morePaige Kelly is used to weird--in fact, she probably corners the market on weird, considering that her best friend, Dottie, has been dead since the 1950s. But when a fire demon attacks Paige in detention, she has to admit that things have gotten out of her league. Luckily, the cute new boy in school, Logan Bradley, is a practiced demon slayer-and he isn't fazed by Paige's propensity to chat with the dead. Suddenly, Paige is smack in the middle of a centuries-old battle between warlocks and demons, learning to fight with a magic sword so that she can defend herself. And if she makes one wrong move, she'll be pulled into the Dark World, an alternate version of our world that's overrun by demons-and she might never make it home. less