cw. trauma, abuse, neglect, and bullying.
rewriting danganronpa's portrayal of a DID system, because whilst I love danganronpa, personally I found it promotes way more harmful DID stereotypes than anything else. so, coming from a system, here's a healthier take on toko's DID and how i think it could have been written better. note that this is only a fan interpretation and personally how i would have liked to have seen it portrayed. toko uses she/her, syo uses she/they/its.
toko was an unwanted child and was raised by her mothers and father. she wasn't looked after properly, and often was forgotten about, which links into her passion for literature; as a child who wasn't fed correctly, and was punished by being forced into a closet for days without food, toko turned to manga as escapism - which her mothers disproved of, and would dispose of any and all manga toko would bring in, berating her for enjoying it (which ties in to why toko has such a strong dislike for manga, she was raised into believing it was cheap literature that she shouldn't have laid eyes on). bringing manga in was punished by also being kept in the closet without food, where she'd be hit by her mothers if she protested or made any noise whilst in there.
due to the abuse and trauma she suffered, toko developed DID (disassociative identity disorder). she wouldn't realise it for many, many years later - though, there were signs that showed throughout her high school life, the first encounter being in third grade when the money was found in her desk that toko was absolutely certain she hadn't stolen.
there were more instances that followed this - her having "outbursts" at her parents that she wouldn't remember, waking up with scratches on her legs, aching and brusies over her body from alleged fights, finding food wrappers from foods she wouldn't even be allowed, and the most disturbing of all, finding diary entries that most definitely weren't from her. these diary entries were confused ramblings from someone who had no idea where they were but often spoke out of anger and frustration. in-depth rants about her mothers were written, alongside how her father should be doing more and was a coward for not intervening. toko didn't recall writing any of this, and knew something was wrong, but couldn't go to her parents with what was going on, nor could she go to her school with what was happening, because it would all go back to her parents. the diary sign offs were from someone who identified as "syo", and all toko could gather was that syo was a lot more violent, and seemed to responsible for all the things she was being blamed for.
this led toko to researching what could have been going on with her - and after much research, she came to the harrowing conclusion that syo was a part of her, and was caused by the horrid upbringing she had. though, toko tried to ignore that - because she was sure plenty of other children had worse childhoods and hadn't turned out like her. so toko ignored it, as best as she could, and tried to ignore the fear that came alongside learning that there could be someone else sharing your body, and that that someone was particularly angry.
however, syo didn't share that same sentiment. syo had found the books toko was reading, and had found answers to questions that they had had. unlike toko, syo was interested in finding out what her other part was really like - and so made an effort to research ways of getting in contact with other alters, learning more and more about system terms so that they weren't so alone and had some company. it wasn't easy, and took several months before any contact was made internally, but in the meantime, syo left notes for toko to find. syo was completely unaware of how scared toko was, however, at learning about syo's existence.
eventually, internal contact was finally made and syo got to "speak" to toko. it made everything incredibly more real, and daunting, and part of toko was convinced she'd made all of it up when reading into it, but syo was there, and seemed to be able to recount memories vividly that toko had no idea even existed, but matched up with everything she had been told about what she had allegedly done in the past, going as far back as to recount when toko had been caught stealing (in all fact, syo had been hungry and figured it would be fine payback for all the times they had been bullied to take the bully's money so they could eat).
it was like that for months, syo sometimes communicating with toko. toko had figured out one main thing that managed to get syo to front without fail - blood. there were other triggers, but toko couldn't figure them out, for they were far too niché or coincidental in timing.
it was only until they were enrolled in hope's peak that toko (and ultimately, syo) were finally given any proper support. toko wanted final, decisive answers and hope's peak was supposed to be a safe place. so in her first year at hope's peak, she explained what was going on to the school board, mainly out of fear that syo may get them both kicked out. to her (albeit, very stunted) joy, she was taken seriously and she was placed in psychology sessions at the academy.
so, with that lengthy backstory written out (which is probably still missing things, it's 5am and i have had no sleep but have been fixated on finishing this for a few days), have some headcanons:
syo is definitely both a persecutor and a protector (some may argue a persecutor is a type of protector, others may not, so for the sake of clarity, she is both here)
toko hates admitting she's a system, because then people either ask her intrusive questions about her disorder or pity her for having a bad childhood
toko doesn't hate syo, per se, however she is deeply scared of their temper, despite knowing syo isn't trying to scare them
syo is eccentric. hyper, excited, the opposite of toko in almost all aspects, except for the fact that they also find it hard to accept friendship and kindness
the class were made aware of syo's existence after she completely snapped at byakuya for making toko cry - leading to a pretty messy situation where byakuya had to go to the infirmary. syo isn't too keen on byakuya. at all.
makoto was one of the few people who took the time to understand toko, and consequently, syo. he didn't understand entirely, and sometimes still messes up with knowing who is who.
syo is also the only one who remembers why toko is afraid of water. they refuse to explain why, however.
toko is worried there are more alters that she's unaware of - if syo has been there for so long, who else may be there?
toko also worries that people prefer syo's more bubbly personality over hers
the most terrifying part of the disorder to toko, is not remembering anything. to syo, it's that people may try to take toko away because of something they did
if anything, toko is grateful for syo being there - though, she would never admit it
they also tend to communicate through letters and notes, typically because it's easier
