Ugh, this chapter was tough to get through for me. But, like, in a good way. It dragged up a lot of feelings seeing how Rinne never prioritized herself. As a kid, she has given up a lot of the things she liked in order to try and be more supportive/protective of her sister. I relate to this so, so much. Hell, I am reading this chapter right now while waiting in a parking lot to pick up my wife because she isn't allowed to drive due to a chronic condition. In a very real sense, my life is controlled by the limitations of my chosen partner. The main difference between myself and Rinne though is that she didn't have the ability to choose her sister, but she also doesn't have to live her life constrained in the same way.
I was concerned last chapter about this new character, but if she is going to be the tool by which we explore Rinne's character like in this chapter, then sign me up. I hope that we can see Rinne rediscover herself as an actualized individual, instead of being defined by her sister.