I meant, to be fair with how it started, it makes sense Yuder never knew. They had a strictly physical only relationship and Kishiar kept a lot of things to himself because he knew he was dying so it was pointless (unlike present time where he can be more honest)
Also Yuder was barely 20 back then, there was a lot of things he didn’t knew because he was so young and lived far from society most of his life.
No, I don't think there were any other known fated pairs like them (even in current timeline I cant tell if fated pair exists outside of these two cuz they have a really special connection, if there are other cases theyd probably be rare). Novel says he met with other couples who awaked second gender but he couldnt find instances like theirs.
I believe that Kishiar has been eyeing/liking on Yuder since the 1st life. As for Yuder he was soo DENSE of not knowing it until his death (︶︿︶)=凸
Read the novel. The slow burn, the WAIT WORTH IT..