I just read the whole thing so far without coming to the comments at all, having my own thoughts about everything. I was thinking about how our world has a sort of "no forgiveness" feel to it, like, if you do something bad once in your life and now you suffer: good, you deserve it. No catharsis for you, go ahead and die.
I was thinking about how nice it was that this manga had a different perspective: that a perpetrator also has the right to move on from their wrongdoing of the past, that they also deserve to live, even though they can't take back the pain they've caused.
Then I came to the comments section. Of course there are too many people with a "no forgiveness" world view, that it's somehow selfish to want to move on. These people think they've never done anything in their lives they would need forgiveness for, but I can assure you, no matter how strongly you believe you've lived a perfect life and never hurt anyone, you have. You may have even traumatised someone (I have tiny one-off things that traumatised me that the perpetrator would never have realised, I'm sure you also have some).
So my rant is basically: bah, why can't people understand that we're just human and need forgiveness from ourselves and others, and to be able to move on. Ruri doesn't have to forgive her, that's for sure. But both of them need to be given that option, and Shizuku needs the catharsis of forgiving herself, and for someone else (Kaori) to forgive her as an outsider too. Ruri possibly also needed to confront the idea at least once in her life that her bully is also just a person, not just an evil entity, so she can get more of a perspective on the mistakes people can make in the world (again, not necessary for her to forgive, but it's a good thing to have more of a full picture of the world).
Yeah, and as for the most recent chapter: I've been thinking for a while now, how did Kaori expect this to go? Yeah, she wanted to reach out to a classmate and help her to be closer to her old self before she most likely passes on, and especially once she found out Shizuku was suicidal, but then what? Make the loner with no one rely on you, then disappear forever, leaving her even more confused and alone than she had been. Her "let's break up" reaction kind of shows how poorly thought out the ending of her plan was. If she had told Shizuku herself much earlier, maybe some of the pain could have been avoided.