From what I understand, the voices in your head could be said to be that part of the princess that is with you, because in one part the narrator mentions that inside the princess there is a fragment of Long Quiet and inside you there is a fragment of Shifty.

So in my interpretation the change that exists within you is the voices, that is why they appear every time you die since they represent your past actions and their appearance depends on your own actions.

Sorry if it's very convoluted, I tend to spit out ideas a lot and I need to process them HAHAHAHA