The Devil Is a Part-Timer!, Vol. 9 (manga)
Available for back-order
DISTURBANCE SEASIDE! The Devil King is on the beach, but there's no time to relax! People are packed into the eatery, and Maou's crew can barely keep up with the demand. Looks like the girls will have to come to their rescue! Everything's fun on the shore, but with the appearance of Maou's military adviser, is there trouble on the horizon?