庇護祭 (Higo-sai)

Background
Miku and Rin were part of an organisation that tried to﻿ quell the cult of people infected with the masks. One day, Kaito was infected by the mask and Miku was forced to killed him before any more damage was done. Feeling weak and disconnected with how she killed him, the mask got to her and she was infected as well because of her vulnerability. Rin, wanting to save her friend, confronted Miku and killed her unintentionally.

This song has entered the Hall of Fame