In order to be with Miku, Rin gave up his wings and became a falling angel. He made a wish to be a boy with wings and feathers. On Miku's wedding day, Lian appeared. Miku seemed to see the back of his beloved angel and fell in love with him.
I traded my life for Miku's. Finally, only the last dyed feather is left.
Even if they fall into the underground abyss, they will still cling to this oath and continue to cling to this unspeakable evil. I hope that when the fruit of sin is completely rotten, we will meet again in the next reincarnation.