I read a theory from someone that they are a lover before apocalypse but tragedy struck Guwon (which explain the stitches on his body) and Teach desperately try to save Guwon to the point of breaking taboo by bringing him to life. And so the god of something angered( the dead comes back to life too) by teach curses teach and guwon to be trapped in a perpetual loop of death where each time they remember they would die and repeat the cycle again
I read a theory from someone that they are a lover before apocalypse but tragedy struck Guwon (which explain the stitches on his body) and Teach desperately try to save Guwon to the point of breaking taboo by bringing him to life. And so the god of something angered( the dead comes back to life too) by teach curses teach and guwon to be trapped in a perpetual loop of death where each time they remember they would die and repeat the cycle again