i totaly imagine this(in assasination classroom)
If y/n reject yandere gagushu and be with yandere karma (and karma will totaly be pround of it)
And years later when turn adult and y/n and karma have a child and be in Kunugigaoka as i know gagushu is probably the school principal(he take his job by his father) and he will SO TAKING HIS REVENGE ON Y/N AND KARMA DAUGTHER/SON
(I think yandere gagushu will hate him/her more is she/he look like y/n because that will remind that he loose)
The only major flaw I do see with this is that I don't think Karma would let his own child go through this experience. Whilst I do agree that he would be smug and flaunt the fact that he got you whilst Gakushu didn't, there is just no way that he wouldn't know that Gakushu is the new principal of the Kunugigaoka Junior High School and send his own kid there willingly.
As much as Karma is capable of being quite an asshole at times, even to you, I just cannot see him putting his own child through that much trouble. He'd just send his kid to another school or move away altogether.
