Playa Escondida Series by Michelle Moore

Jay's an average lifeguard. Sure, there's the family curse—a connection to a demon who shipwrecked on the coast centuries ago—and being the last heir to the heretical sect of monster hunters who failed to destroy that demon. So he's mostly an average lifeguard. Dan Green wants nothing more than to find and tag a sea turtle, and finish his degree. He's starting to think he should have picked a different beach... moreJay's an average lifeguard. Sure, there's the family curse—a connection to a demon who shipwrecked on the coast centuries ago—and being the last heir to the heretical sect of monster hunters who failed to destroy that demon. So he's mostly an average lifeguard. Dan Green wants nothing more than to find and tag a sea turtle, and finish his degree. He's starting to think he should have picked a different beach. Even his degree isn't worth getting tangled up in old ghost stories, demonic curses, and a monster hunt 400 years in the making. But Jay? Jay just might be... less