is Kage even real? Her name too is a bit on the nose.
My theory is she is the manifestation of depression or an entity only perceived by depressed individuals, since Hikari didnt know who Kage was in the beginning, and seems to have forgotten her in the end. Kage knows the way to treat Hikari's condition isn't simply fooling around but actual medical intervention. She knows she'll be wiped from Hikari's memory, cue "Please find me again, nya"(p38), and distraught Kage (partly bc she wished it hadn't come to this) (p39).
That begs the question, what abt her sisters and what should be made of the trash house? Idk maybe catgirls' role in their society is unpaid mental aid and since no one but ppl in crises can see them they're getting abused freely lol I'm running out of steam