Kaede & Suzu 3

Kinda feel like this should include a vanilla tag. It's obvious that Suzu loves her sister that way and the unspoken feelings that are communicated with their looks and expressions practically scream it.

The artist already said that will never happen. At least this MC wont give it to anyone but kaede

that exactly. the better looking and more likeable one (from what little of their characters we are shown) is left out in 3 parts of this series already.

I cant seem to be able to reply to your other comment so I'll just say it here, it was during a live stream on pixiv while making the K&S stand alone art of them both bending over while fully clothed. I can't recall where I first saw someone translate what was said then but that is where I heard it.

On the plus side, it means that we get more beyond what's in the book.
With how hentai mangaka bounce around between series and frequently just write one-shots, it's not all that uncommon for them to end up with series not being contained in a single tankoubon though, even if they would have all fit in one if they'd just been released in order. If anything, sadly, getting story continuations seems to be a bit of a luxury in the land of hentai.