Hell yeah side couple! Good to see cucked-chan gets a bestie as a lover soon. I do wonder if they try to use the future machine with Sakiko, the same error that showed up with Kako would occur — since i think the endgame will be Kako “disappearing” because she went to the future, and Sakiko could do to same.
By the way, I have never commented this but it’s really funny that even tho in future Japan two girls can marry and have a biological child, arranged marriages are STILL a thing. 💀