Well, people have been saying that Akane was too cheerful for this series, and I think her well-intentioned but ill-fated advice to Kokoro will cause her to change somewhat. She'll likely blame herself for whatever happens. Alternately, she could end up blaming Kurumi if she doesn't understand the real series of events.
Kokoro has really crossed a lot of lines here. Kurumi making their breakup official caused Kokoro to finally finish snapping and assault Kurumi to try to force her delusions onto her. She even denied Kurumi's ability to make decisions for herself to avoid from having to accept the rejection. But it's even worse than that, since it turns out that Kokoro was secretly spying on Kurumi for Kurumi's mother since the end of volume one. That's a massive betrayal of trust. Yet Kokoro doesn't seem to realize any of this. Also, inspecting Kurumi for "defects" at the start of the chapter, like she's a porcelain doll or something. Kokoro's height was high-lighted at the start of the series and this chapter made it clear why. It's because Kokoro is so much larger than Kurumi is, that she's easily able to overpower her. Hopefully Kurumi can get out of the situation or help arrives by Kudou telling Naoi about Kurumi's call. I did notice in three different frames that there's a pair of scissors next to where the phone originally was.
I generally think that at this point that it's too late to redeem Kokoro's character. This feels like her last stand. My best guess, is that she'll be forced to transfer schools. And her parents' shop might go out of business and they're forced to move away. This chapter was already the third time that the sign for Kokoro's family's shop was shown in the series. And it's named after their family to boot. Kokoro causing such a scandal would likely lead to her family's reputation taking massive damage, which would likely result in a massive loss of customers. So, I wouldn't be surprised to see a big "OUT OF BUSINESS" sign on the building by the end of this volume or the start of the next one.
As for Kurumi herself, she's definitely in a no-win situation. She's obviously terrified, with seemingly no way out. Trying to reason with Kokoro clearly will not work in the state of mind Kokoro's currently in. And trying to argue with her might result in Kokoro becoming even more violent. Though being passive wouldn't likely yield good results either, since it would give Kokoro the false impression that she was right and really can force Kurumi back to acting like she used to, when really that was just a facade and not Kurumi's true personality. Though given Kurumi's words to Naoi in chapter 14 and Kurumi's growth since the end of volume 2, Kurumi holding her ground somehow feels more in character. Plus, the volume 2 leaflet more or less spelled out that Kokoro needs to finally accept things she doesn't want to, even if it's painful, because dragging things out just makes everything worse. Would be interesting if Kurumi getting cornered causes her to get angry enough to show her "dark side" to Kokoro so that Kokoro crumbles when finally faced with a more honest Kurumi.
I would like to point out something about the phone call between Kudou and Kurumi. In Japan, saying someone is "in the shower" can also just be a polite way to say that someone is using the toilet. So, Kokoro trying to frame it as something automatically sexual isn't the "gotcha" that she thinks it is. Though Kurumi will very likely still want an explanation from Naoi about what she was up to when she called. It could create some doubt in Kurumi's mind about their relationship because Naoi did keep her association with Kudou a secret from her, though that's likely more out of the shame Naoi feels for having more or less tortured Kudou when she was younger. There's also the fact that Kurumi and Naoi don't seem to technically be an official couple yet. Kurumi didn't even make dumping Kokoro official until this chapter. So, Kurumi might not be as upset with Naoi as some people might think. The story has in fact, never had Kurumi be direct about her romantic feelings for Naoi. Kurumi's "I might" when asked if she wanted to spend time with Naoi over summer break. To Kurumi not wanting to admit how much she wanted to live with Naoi just a chapter ago.
Speaking of Kudou, she was surprisingly polite to Kurumi during their call. But that could also be because she currently mistakenly thinks of Kurumi as just a toy to Naoi that Naoi will eventually get bored with. Keep in mind, that Naoi has never clarified what her relationship with Kurumi is to Kudou, because she doesn't view it as any of Kudou's business. How Kudou might react is anyone's guess. Kudou being nice might purely be because she's currently getting her way about things. But if she finds out that Kurumi and Naoi are in a genuine relationship, she might not take that well, especially if Kurumi wants Naoi to stop meeting up with her. Or maybe Kudou will mistakenly think that Naoi's only dating Kurumi out of guilt over not picking up Kurumi's call. I'm also kind of suspicious of the hearts theming of the room Kudou booked this time. Even Naoi called her out on it. Plus, the fact that Kudou is now starting to want daytime meet ups when that wasn't seemingly a thing before according to Naoi. So, this situation also seems like a powder keg getting ready to blow. If Kudou is indeed from an influential family, she might try to use their connections to mess with Kurumi and Naoi if she gets angry at them. The volume 3 color pages dream story have Kudou referred to as "director", so that could symbolize that she has some kind of higher status. Though it would also be interesting if Kuwabara subverts expectations and has Kudou become a legitimate friend of both Naoi and Kurumi.
And finally, Naoi is likely going to blame herself for Kurumi's situation. Since she was going along with Kudou's whims instead of being available to be there for Kurumi. And Kudou more or less outed their association to Kurumi, which Naoi was likely deliberately keeping a secret. So, everything Naoi was working towards, her plan to move in with Kurumi after high school, seems on the brink of going up in flames. However, if Kudou does tell Naoi that Kurumi called, Naoi'll likely rush over there to explain things and help Kurumi. But if Kudou doesn't tell her, then Naoi's likely going to have a tough time this volume trying to regain Kurumi's trust. Because Kurumi was set on doing everything herself and never relying on others. Yet when Kurumi finally decides to call Naoi for help, it seemingly only led to more pain. This could be what gets Naoi to cut Kudou out of her life, which would be what finally causes Kudou to act.
Kurumi and Naoi likely have many obstacles ahead, but each volume has made them closer to each other during it, and I doubt volume 4 will be an exception to that. Volume 2 showed that Kuwabara is good at creating feelings of catharsis at the end of a long road of struggle.
