Had to look for the yandere tag when I saw Nina on this page: https://dynasty-scans.com/chapters/were_shin_kawasakis_3_woman_couple_kiss#7
I liked how her negative aura was physically manifested as porcupine-like quills that pricks those nearby.
Both works for this pairing(?) throuple(?) have porcupine quills. I've never watched the original, but I'm guessing it's canon?
A few things:
You're saying you've never seen the anime? You absolutely must watch it! It's amazing!
The "prickles" are visual symbolism used to show when Nina feels like she's being consumed by negative thoughts and emotions. In the anime, they don't physically manifest and are not able to be seen by others (or Nina for that matter).
The other doujin for the throuple is cute. Thanks for mentioning it.
You think I have time to watch anime? Preposterous! I'm much too busy spending all my time reading yuri manga; no time for anime.
Thank you for the recommendation though, and thanks for the explanation XD
Genuinely, if I had to go back in time and choose between watching GBC once and reading yuri manga for a year, GBC clear. Its incredible, worth over a hundred manga for me.