Oh! Thank you for the explanation! That changes the meaning of the wistfulness around growing up and the lines about "I learned to paint my face / to clean my kill". I love the way it reinterprets the song.

Their relationship sounds very sad and very good.

...And also I think I've misosmosed The Untamed, I thought it was all about Flute Necromancer Guy, Guy in White Who Speaks in Very Formal Archaic, and Jiang Cheng. I didn't realize that there were more sects involved!