>>96510176
>What effect does your Stand/Persona/JITE/Idolon/whatever have on you?
It makes Momo more high-strung/impatient inside bleeding/flooding zones and the Idea World, because she has to keep constant control of an hyperactive oni girl. Most of the time [Simply Red] and her are on the same wavelength, but the Idolon is a lot more carefree and cluelessly heavyhanded with her violence. Against monsters it's not such a problem, against possessed humans/nightmares Momo has to make sure she's not going for the kill.

>Does anything change when the shit hits the fan proverbially?
Yes, she does have the Under An Evil Star drawback, becoming more bloodthirsty if her oni blood acts up, and that bleeds over to her Idolon as well. They start torturing opponents to make sure they can get their fun before breaking their toy, not that they wouldn't desecrate the fading remains even after death. Her usual pushy sukeban ways become downright tyrannical, turning even on her allies if they don't fall in line and obey her every order.

As an aside, since the oni whispering temptation in her head is very old, Oni Momo will start adopting a more ancient manner of speech if possessed by madness. Like a demonic sect chud ripped out xianxia slop.