Guys I’ve seen the raws and it kinda seems like it got axed and ended at chapter 12 i think? Because at the end of chapter it’s written おわり (end) instead of the usual つづく (to be continued). Also if anyone want spoilers for the ending (I’m using google translate tho so it might not be accurate)
Yuki is most likely the fated woman as some people already have guessed. But she’s also the yandere kindergarten girl from the flashback. So i think she already like him since kindergarten. Riku response is positive and basically said that if Yuki isn’t here he wouldn’t be alive, and the chapter ended with them holding hands. It’s a bummer if it indeed got axed, but at least it looks like he ended up with best girl so it’s not all bad. Since this is google translated, keep in mind that i might be wrong. And also there seems to be a light novel, but it’s currently only 1 volume so I’m not sure if it’s actually have a different ending or something.
Edit: also i just noticed that at the end of the chapter written “Thank you for reading!” to further support the fact that the manga has ended