Elaborate pls i dont remember :”(
Kihoon saw this image in his dreams in the current timeline where historical timeline yeon(angel) was slumped over with like 6 arrows in his back. I think it was in the car when modern yeon said he would protect kihoon and kihoon remembers that dream and gets really upset about it. They go visit the rock after. So it was strongly alluded to that historical yeon dies in historical kihoons arms. We also know that modern kihoon dreams about sex scene between historical kihoon and yeon, so the flash back definitely has a good couple years on it before the big past life reveal.
Thay we saw hinted to in s1 . Σ(っ°Д °;)っ