"Mayfly" is the 24th episode of the season "Three Vessels" and the 76th episode from total.
Yuzuki realizes that nobody at school or in her neighborhood knows who she is. Ultimately, it is only Tsugumi Shibata who still recognizes her. Tsugumi has given up hope of stopping the Hell Link, and concludes that Yuzuki is not a person belonging to the normal world anymore. Tsugumi notices that all this time, Yuzuki's life was an illusion. When Yuzuki returns home, she finds her apartment in an abandoned state, with a corpse of a girl lying next to a stuffed bear. Ai appears and tells Yuzuki that the body belongs to her younger self, and that she has died a long time ago.