The round up:
Isanuma and her two fellow mean girls are the same three talking behind kurumi in the first chapter, and the implication seems to be that they’ve been needling kurumi for some time which is probably partially why she fantasized about killing her and not Naoi
She also seems to have a tiny tiny tiny amount of respect regarding naois cleverness, whereas Isanuma is just dumb and spiteful for no reason
Naoi probably saw kurumi’s almost shoplift while she was working, so it was likely just happenstance and she hadn’t followed her or something like that
Naoi bailed her out (or should I say PAILED her out hahaha send help) when the mean girls were dunking on her when she could have just let them keep going, but it’s impossible to know if she really wanted to help her or just wanted to monopolize her suffering; suave as fuck taking the flower out of kurumis hair tho
Kurumi is taller than Naoi and I think that’s great
Kurumis dad(?) is in the photo she’s holding on the title page but we haven’t heard anything about him; could be dead for all we know lmao
Naois photo is shattered which is unsurprising considering her dad is almost certainly physically abusive/forcing her to work?
Naoi doesn’t want her time with kurumi to end (she looks like she wants to walk into the ocean in every panel she’s not messing with kurumi) so it’s really hard to tell if she was ever going to post the video (if she doesn’t have blackmail anymore kurumi has no reason to be around her/would probably evaporate into dust anyways)
Kurumi straight up disassociates pretty frequently (the laughing, not even noticing she had raised her hand, zoning out while doing desk crimes, picks at her hands when she’s anxious) so her mom is probably the actual fucking worst person and now Naoi knows that kurumi is also being abused by a parent in some way
Kokoro knows something’s up
Naoi looks like she’s genuinely concerned when kurumi starts disassociating hard at the chapters end (imo at least lol)
Isanuma will almost certainly blame kurumi for her desk (who else would have done it lol) but she has no proof and considering kurumis reputation no one will probably believe her; this could lead to her lashing out at kurumi even more and kurumis already about a pico second away from a complete meltdown
Tldr everyone is making the worst possible decisions and I love it okay I’m done
