It couldn't fit through the front door, which is somewhat suspicious
The constant weeping may suggest remorse over his actions, or it could just be.maybe it's time to stop now. Stabbing the creature changes his eye from a malicious red to a clear blue-perhaps a suggestion that her striking out against him opened his eyes to how much he hurt her. In her dream, he leads her to her assailant so she can accept the trauma.
Given that it's phallic, it could suggest that the rape took place in the boiler room of her school-a janitor or teacher, perhaps? Under this logic, Masada, who has "sensei" in his full name, may have been a sympathetic music teacher that suspected what was going on, but was never able to prove it. Inside is a boiler room, inhabited by an enormous, one-eyed, constantly crying creature β.
In that case, "Nasu" is obviously "eggplant" (θ).