The Snow Queen Mask is a mask used by the St. Hermelin High School drama club to perform the titular role in . For unknown reasons, the mask is haunted by the Night Queen. The spirit of the mask speaks to whoever wears it and drives them to suicide by playing with their insecurities. There are four known victims of the mask: Kumi Hirose, Michiko Matsudaira, Yuriko Yamamoto and Tomomi Fujimori. After Tomomi's death, Principal Ooishi ordered that the mask should be put away in order to prevent any more deaths.
During the events of the Snow Queen Quest, the Boy with Earring finds the mask in a box sealed by s inside the school gym storehouse and retrieves it. Saeko Takami wears the mask and is taken over by it, triggering the events of the quest. In order to save their teacher from the mask, the party must collect Mirror Shards from the three towers and complete the Demon Mirror.
If the party manages to gather at least eight shards, the mask will detach itself from Saeko, grow in size and attack the party as Lady Masquerade.