Here's my own understanding throughout the show, I think Shion is a very relatable character, I find that there's a little Shion within us, a Shion who lacks experience outside that big wall (world) and doesn't know much about bad things that happen in life. Shion sees good in people, and if that innocence is put aside by another person who experienced so much pain and lost, everything starts getting messy. Lol, yeah that's it, that's all I could squeeze out of my brain. Definitely you should check it out.
By the way opening and ending song is 10/10, amazing!
