Did a lil bit of digging on what really happened in the end

found this explanation about it online by @peoniesandboyslove From what I got, his little sister, Yuju, were killed by her kidnapper, and Giju tried to denied it immersing himself into methaphysical thoughts, convincing himself there was a little bird into the box, but the panel where Yuju has wings, snuggled in phetal position, left no doubts about her tragic destiny. The worst is that we also can see Giju’s “dad” (the pedo bastard) wanting to make Giju the culprit of everything bad he had committed, even of his own rape, as if Giju was the one who seduced him. ???? We also got that when Giju’s mom discovered his husband’s atrocious plans, she told Giju to leave their house in order to protect him as she could, making it clear that she acted out of love, not hatred towards him. ???? Unfortunately, after knowing about Yuju’s death, mom set light to her own house, committing both suicide and murder (dad died too), and also Giju killed himself by jumping off a really high spot. Apparently, he cannot stand such a pain from the lost of his little sister. At the end of his eternal falling, Giju found again Young-do, who also died due to a killing order from his old boss, and he greeted his lover in the afterlife, saying that in this dimension, this time, he will really be able to keep him safe