Well, that was certainly unexpected (at least to me).
If it weren't for the fact that it's her own sister we are talking about, I would have no doubt that the last few pages imply that she likes Aki.
If we rule that out (I certainly hope that's the case), a second option would be that she has a crush on Shiho, which would also be pretty strange since I don't remember seeing them interact or even Miki mentioning her (I'm sure she did, but nothing relevant). Still, I wouldn't dislike it, to be honest.
A third option would be some trauma related to her old boyfriend (which she mentioned to Hima at the beginning of the series). Although, being a manga where men basically don't exist, I doubt the author wants to put too much emphasis on anything related to him. Maybe Miki lied, and she never even had a boyfriend to begin with? Maybe it's just that she feels more lonely and "left behind" now that Aki has found a partner?
Another option would be that the author came out with this out of nowhere to extend the series, of course.
In any case, I hope Shiho plays an active role again in this Arc, helping Aki with whatever problem Miki is facing.
This isn't super surprising to me, we always knew Miki was a bit of a siscon
Huh, I don't think I ever suspected that. Maybe I should reread the first chapters.
Yeah I always thought she was only fond of her sister, as a sister. Not a siscon, so I didn't see this coming myself.
Ummm... I don't like where this is going to be honest. Like please be something else, please. At least the “incest” plot in Citrus they are half sisters that didn't grow up together or were raised by their parents, they were strangers, Mei and Yuzu's parents relationship is weird, not the point. Here, in sasakoi if they are going that pat is blood related incest, it's gonna ruin this story for me.
Adding I was expecting a messy story with HajimexMomoka and being in love with the girlfriend of your deceased sister.... please no incestplot.
I think in Ctirus they're step-sisters, half-sisters they would be blood related still. Half-sibling means your parent had a kid with another person, so they're half related to you, but still a sibling all the same. Step-sibling is when your parent remarries and they have kids already. Which is the case in Citrus if I remember correctly, where Citrus being controversial for the "incest" is really an almost non existent factor, due to them not being blood relations and dating almost as soon as their parents married, they didn't grow up together or anything. It's basically a way for Citrus to be "taboo" and have the characters live together.