If you're insecure about main couple then take a look at author's drawings on twitter
https://twitter.com/ORYU____/status/1117644154660507648?s=19
those are not the main characters
https://twitter.com/jaxx_s2/status/1116550718666633216
walk on water 3....?????
i think '3' means the volume of original novel.
Finally!!! I'm so happy for them like they are my real life friendsi wish them all the best