Let’s put it like this. “Silence” characters are the original ones. The “silence” Huimin suffered so much that he drew a perfect world where he and Iheon are not destined for tragedy. That’s the world from which the young Huimin comes, the alternative reality where they lived better and where the original story is a book. Now, the poor Iheon had to be reincarnated in both worlds knowing the full story first handedly. So he adapted to young Huimin’s world and tried for them to fall in love and live happily (last chapters) but, in the world of Silence, it seems that Iheon has been reincarnated several times and has seen the same ending over and over again. That’s why seeing this completely “new” Huimin that has no grudge against him is so refreshing. However, young Huimin just noticed he is the alternative version of the original Huimin and has also had these “illusions” of the past painful memories of the original goods. It’s a mess lol. I haven’t read the novel, so this is my take on what has happened. Hopefully you kinda get my messy explanation
The duck is happening?