Bad Ending 1: Tei overdoses Eri's drink and she loses her memories and voice, now working alongside Tei in Banjul.
Bad Ending 2: Tei apparently rapes Eri and injures her knee, rendering her catatonic the next day.
Bad Ending 3: Eri allows Tei to 'break' her however he wants. She loses her voice and emotions, becoming a sort of 'living doll' for him.
Yeonho's bad endings, with the creepiness factor upped.
Bad Ending 1: Eri becomes just as creepily obsessed with Yeonho, as he is with her, and begins to abuse him, similar to how his previous owner did. It's frightening to see the usually sweet Eri become so twisted.
Bad Ending 2: Yeonho snaps and tries to kill Eri, strangling her, so that they can be together forever. Then Tei arrives and interrupts Yeonho.And then it gets worse. Tei reveals that he's disappointed in how 'easy' Eri is about being destroyed, then demands that he do it, if anyone was to destroy her. Tei then proceeds to kill Yeonho and approaches Eri...
In Tei's route, instances where Eri cannot remember simple things and you realize it's because someone (likely Nameless) keeps ripping up her diary pages, forcing her to lose her memories.
Gets worse in Red's route where Nameless overdoes it, rendering Eri to forget a whole lot of things and become incapable of forming new memories.
During Red's route, the extent of Eri's memory loss becomes frightening. Red stays by her side every day, the entire time and they repeat the same motions. She wakes up, she doesn't remember anything, has to read little notes to remember the names of her friends and make it through the day. Then they practice for the play, go to bed... and she doesn't remember anything. Your loved one cannot remember what you did, leaving you as the only one to recall anything and no idea if their memory will improve.