To be clear it's impossible to make mizuena tragic without killing Ena first. Want to have Romeo and Juliet but mizuena? Good luck with that as long as Ena is around. She will never allow any story involving Niigo to end in tragedy, even if she doesn't fully understand the narrative. The only way to doom their narrative is to get rid of her.
What I'm saying is if you want the tragic narrative to win, killing Ena is your win-con












