I'd seriously be traumatised if I were Isei. Imagine seeing your lover die so many times. This time it might have worked out perfectly fine, what if 20 years later Ban dies again and Isei would travel to the village himself just to get the miracle box and start everything all over again? When you know there's a way to cheat death, you'd do it over and over again.
Plus I was so sure smthg very sad was gonna happen like Ban was already married or he never cross path with Ban. But thank god it was a happy ending(⊙…⊙ )
I see a new ship (๑•ㅂ•)و✧