Absolute Duo Vol. 4 (manga)

The Koryo Academy’s island branch campus is an ideal place for some extra training–and for its ladies to show their stuff in swimsuits. Things are looking up for Tor. He may have to put up with the ongoing efforts of Lilith to seduce him away from his Duo partner, but the island is a place to unwind and meet old friends. Unfortunately, all that is not to last: a mysterious enemy is preparing to make a move against the Academy!