18+ Bloody Maiden: Toomarimiki no Shima

12 members of the Fujimigahara Girls' Academy's Naginata club arrive at a remote island belonging to the club president's family. Legend has it that the remote island had long ago been the hideout of a group of extremely cruel bandits, and that priceless treasures - the fruits of their plunders - are still hidden somewhere on the island.

All is well until their club adviser and two members are brutally murdered. Thereby the curtain rises on the surviving girls' life-threatening battle with a bizarre masked killer...

(Source: Village Idiot)