In general, Monophanie is considered "the cute one", with a tendency to do cute things like trying to solve the killing game via rock-paper-scissors, or suddenly falling asleep, and liking flowers. She is also mentioned to dislike nasty things like gore and bugs. When the siblings begin their usual fighting, she often plays the mediator and seems to dislike arguing, but in the end, she always ends up joining in the fight. While often seeming very gentle and sensitive, she also has a tough side, like when she threatens to defeat all of her four brothers all by herself with her Exisal. She also hits Monotaro multiple times in the head with a frying pan in an attempt to fix his memory. She has referred to herself as a "strong, sensual woman" and says that she should't be underestimated because she's a girl.

Despite her kind demeanor, she can speak in mean and vulgar manner just like her father and siblings, and has a ruthless side. She tends to say things with somewhat mixed messages, beginning her sentence with kindness and then ending it with cruel indications. She may express worry towards others, but ultimately seems quite cruel like her other kind. Being a Monokuma, she indeed seems to be evil and messed up even though sometimes appearing nice.