In book 7, Eris’ slightly-ditzy mother misread her letter home, and got the idea that she was in a serious relationship with both Kio and Aoi. “Not that there’s anything wrong with that,” and Mom went so far as to reassure Aoi that Catian scientists had plenty of experience helping interspecies gay couples have children together. Cue blushing all around, and stammered explanations of the actual state of affairs.
Except… Aoi really is developing feelings for Eris that she doesn’t understand, and that her emotionless-killer childhood hasn’t prepared her to deal with. It’s a tangled-up mess of friend, comrade, big sister, little sister, rival, and, most recently, as she helps Doctor Dyureru give a feverish Eris a sponge bath, “wow, she’s hot”.
Where’s it going? No idea. At this rate, I think we have to wait for Eris to go into heat again for anything to happen in this relationship. Given that the good doctor grins to herself when she sees Aoi’s reaction, and also listens in approvingly a bit later as Aoi pulls back just before blurting out to Kio that she wants to be his wife, I suspect she won’t be providing any heat-canceling pills next time. And since Captain Kuune is also gleefully shipping this trio, Kio and Aoi will probably find themselves locked in a room with a horny catgirl and a week’s worth of food.
Note that despite my expectations that book 10 will have major plot-advancing action, as of the end of chapter 5 (of 9), Eris’ sponge bath is the most significant event.
“Not that there’s anything wrong with that.”