Prior to the Tragedy, Komaru had a cheerful and optimistic personality, somewhat similar to her brother. She loved Makoto, telling her brother to do his best while enrolled at Hope's Peak Academy. As of Danganronpa Another Episode, Komaru began as a somewhat hypersensitive and quite cowardly character. She wavers between hope and despair as a result of her forced imprisonment. She doesn't want to have strong hope, because she believes it will be lost eventually, leading to worse despair. She has low self-esteem, considering herself boring, ordinary and weak. After being encouraged by Toko Fukawa, she gained a desire to at least try to escape again. While she finds escaping hard and fighting even harder, she is willing to fight off hordes of Monokuma Unit robots as she tries to survive the world's current catastrophe and find her missing family. Komaru shows some childish traits, such as being naive, reliant, and easily excitable. She also has an 'unusual' kind of pride, as she gets really worked up from the puzzles of the Monokuma Kids and brags towards the kids when she solves them. She is also very gullible, which is revealed when Toko says certain things that are obviously false, and Komaru easily believes them to be true. She is rather innocent as well and doesn't seem to have much interest in romance nor sexual thingsーas a great contrast to Toko, she never seems to get flustered by handsome guys and just treats them like any other people. Though, she once tried to claim she has lots of experience with dating and sex because she was afraid Toko might make fun of her. It's been stated that in the past some creepy guys have taken interest in her, supposedly because of her gullibility, and it's been shown that she isn't very good at noticing their intentions. Komaru has short, dark brown hair with a tint of green, and de-saturated green eyes. Overall, she is described as very plain-looking and "normal", which seems to be the same way people describe her brother. She wears the St. Koa Girls Academy uniform, which consists of a sailor fuku with a white blouse, a red necktie, and a turquoise collar, line trim, and skirt. There's a school crest on the bottom right of the back of the collar, necktie, shirt pocket and the outer sides of socks and also wears a blue striped bra and panties.

Due to the constant bullying she faced as a child, Toko developed low self-esteem and severe inferiority complex. She is highly suspicious and paranoid of others, frequently and baselessly accusing them of thinking her as nothing but disgusting, ugly, unwanted, or combined altogether. She becomes very self-conscious about herself, from her appearance to negative personality, so she often verbalize these thoughts before others can. She has an unusually quick tendency to self-victimize, and is incapable of thinking that others might see her from a positive light. On top of that, she constantly projects hostile intent onto others, assuming that people approach her out of pity, on a dare, or wanting to hurt her, whether verbally, physically, or otherwise. She is extra wary of others finding out her secret and the possibility of switching to her alter on accident before being outed by Byakuya. Toko has become so accustomed to verbal abuse that she occasionally responds with flustered or oddly pleased reactions. She often showcases these masochistic tendencies through her interactions with Byakuya. She appears to have a liking for being tied up as well, which leads Komaru to believe that Toko's experience of being tied to a jungle gym when she was younger was a formative one. In School Mode, she feels slightly disappointed when Makoto clarifies that he won't tie her down with a rope. It isn't uncommon for Toko to project her own perversion onto others by accusing them of thinking dirty thoughts. On top of that, she comments on other girls' bodies as often as she self-deprecates about hers. Aoi becomes her frequent target, as she not only demeans her morality out of envy for her curvaceous build, but also made many degrading jabs about her appearance. Toko also finds Aoi annoying in general, calling her "idiot swimmer girl", "sports idiot", and "stupid cow", among others. In spite of this, she seeks protection from Aoi at one point, claiming she would use her as a meat shield in case of a danger. Toko is of average height and possesses a thin figure. She has long dark purple hair which she keeps in two braids behind her, grey eyes and large wire-rimmed round glasses. Hidden by her long skirt are tally marks carved onto her upper thighs—a count of how many men Genocide Jack has killed. On the left side of her chin is a small mole. Toko wears Riverbank Girl's High School purple sailor uniform with a noticeably lengthy skirt compared to those worn by other girls. She also sports her former school badge on her left pocket and has her school emblems embroidered on both upper sleeves. Her alter keeps her scissors in a case on their right thigh. She also wears white socks and brown loafers.