Holy Necklace (聖なる首飾り Seinaru kubikazari ) is a key item in Knights in the Nightmare that belongs to archangel Marietta. It is used to reset the Boss Meter for her corresponding half. In either path, Holy Necklace is found by breaking the rock in Scene 5.
Holy Necklace enters the story the night the Mehse Tower is destroyed, when the angel comes down from Asgard. It is dropped by Marietta when, in time of doubt, she senses Zolgonark's presence and flies away to Aventheim Castle.