Mugyeong is an orphan taken in by Yukio's brother because he's athletic and shows potential. But he's Joseon and at the time, Joseon people were targeted by racist Japanese people so he was constantly bullied. Aside from Mugyeong being Joseon, Yukio also felt inferior to him because his brother favoured the kid. So he bullied him out of jealousy, he wasn't really racist.
From what I understand, Yukio misunderstood Mugyeong's actions and thought he has feelings for him so he started to see him in another light and developed feelings for Mugyeong. And because he was interested in writing, he wrote that love letter with metaphors and stuff. And also we see that Mugyeong has grown soft towards Yukio as well. He was shocked and passed out when he saw his letter and in the flashback we see he returned Yukio's stuff that he forgot to take with him.
On the other hand is the crimson bird, which I assume is a group of revolutionaries opposing to the current situation and they are doing their thing, but Mugyeong is being accused of working with them.
This is my opinion on the whole thing so far. I might be wrong tho
Omg thank you so much for taking time out of your day to explain to me :)!!! Ok I completely understand now and I’m excited to see where this story goes ヾ(☆▽☆)
Gurl no problem
I'm glad I could help <3
Okay i really like this story it’s very different but I’m so confused someone please explain lol