I think she can grow into a good person - but she's so morally bankrupt at this point that you'd have to call the leg warehouse in order to search for something for her to stand on.
Akira is a horrible person, true, but the things he did were never to hurt other people. He's like a very chaotic neutral, his actions sometimes benefit others, and sometimes make other people lives' worse (and even then there are lines he doesn't cross willingly). Kirin goes out of her way to torment people, and what's more ridiculous is that she doesn't even want to be malevolent, that's just the option left for her because she's stupid.
I don't see Akira blackmailing people into doing anything. And when Nodoka does it, she doesn't cop out and go with "but you blah blah blah" - she says "I did it because I wanted to and that's how life is". I hate Nodoka, but I respect her in that way. Now, is Kirin changing? yes, I can't deny that. But for her to be able to come to Akira and ""stand for her sister"", when she's the same person that sexually assaulted and replied with glee with the thought of her classmate being raped by him would be like Yuki taking the highground on someone abandoning their children. Or Akira judging Haruka for being a predator, for that matter.
I don't think Kirin has changed enough to be able to even speak from a place of "well, it's exactly because I fucked this up that I'm telling you not to go down to my level" - Yuki has. She's earned this, especially because she will not judge you regardless. Same as Akira towards Haruka. For Kirin to stand up for Karin against Akira in any sort of way is just preposterous imo. She can be mad about not being told, or invited idk - I'm fine with that much.
