I found something here:
My character is a girl and the one saying this seemed to be Haruki
Regarding theories and ideas, probably our kitsune will win.
MC's teacher helped her when she let the other yokai get out alive, but now there's no way to help my MC out of this mess. Personally, if I was in her place, I would be happy. Discovering that we are risking our lives to some guy get immortality would make me want to stop being an Onmyoji.
I would take this chance and fake my own death, the yokai was strong, it makes sense. I would run away, change my name, cut my hair and sell some of my kimonos to get money... then I would become a wanderer, helping people with yokai/ghost problems.
Or the history would go the same way "My Girlfriend is a Gumiho", MC suffers a mortal wound and the kitsune gives her a fox bead to "save" her.