Crash Station
Member
Both (memory wiped) casts were subjected to the same kind of Despair and it resulted in similar killings (i'd even argue that the DR2 cast had stronger unity, since they were pretty much forced into killing each other), so one can only imagine what Junko did to the DR2 cast to turn convert them into the Ultimate Despair.
I'm only talking about the non-memory wiped part. It seemed the DR1 cast were confined to the school at a time when Junko was compliant (at least on the surface). We don't know what the DR2 cast was subjected to, but it seems pretty clear they were out in the world seeing some of the craziness firsthand.
Their emotional vulnerabilities aren't exactly riveting stuff. As far as I can see there aren't a lot of rape victims in the cast. Mostly they just suffer from the sort of things that ordinary people do. I could buy arguments for a few of them, but generally it's pretty tame stuff. What was Ibuki's issues, that people didn't like her new style of music? Gundham has social anxiety? That isn't the sort of thing people murder over. If worse shit went down, we aren't given the specifics.
See, this is a reason I find the cast compelling. Just the uncertainty regarding their transformation to Ultimate Despair. You're left to think "what could have happened to these kids to drive them to that point?" and you can just let your imagination run wild. Maybe one of the teams Nekomaru was managing was slaughtered. Maybe Ibuki tried to reconnect with her former bandmates, but they were raped and killed right in front of her eyes while she was only subjected to one of these things. Maybe Mahiru found the body of the mother she respects so much in some sick and twisted position with a photo on top of her smiling severed head that says "say cheese". The point is we don't know, but we're lead to believe it was so damn horrifying that even a relatively nice cast of characters with some mild insecurities (barring a few) were turned into monsters without a shred of humanity.
The only reason we know for sure is Hajime, and his despairification makes sense considering how much his brain was fucked with.