Toko bears a great resemblance to her ancestor, Nezuko Kamado, having the same waist-length black hair parted to the left side of her forehead, though her hair tips are much darker than her ancestor's and are closer to an actual red color than Nezuko's orange. She has round, pink eyes with prominent eyelashes and thin eyebrows.
Toko wears her school's standard uniform, consisting of a light blue long-sleeved shirt, black skirt, black ribbon necktie, and white vest. She also sports her uniform's black knee-socks and brown loafers.
Towards her brother, Toko shows great aggravation and animosity, often berating him for his antics and telling him off for not studying. At times, she resorts to physically attacking Yoshiteru, such as kicking his back or tugging on his ear.
However, when Toko is with Kanata Kamado, she instantly loses her angry demeanor and instead becomes much more jubilant, especially if Kanata compliments her. She is still easily annoyed by her brother if he interrupts her and Kanata's activities.
Toko's personality shows that she doesn't believe in "superstitious" things, such as Zenitsu's journal about their journey to fight back against the demon race.
As an older sister, Toko is always telling off him to focus on his studies, especially when Yoshiteru was reading Zenitsu's book. Although she was always angry at him, both Yoshiteru and Toko care for each other, showing they have a good relationship.
Kanata is Toko's second cousin. When around him, she often switches to a happier personality instead of her angry demeanor, and they often compliment each other. Toko appears to enjoy holding his hand.
As an ordinary human, Toko does not hold any special abilities or powers.
- Her first name contains the kanji for "lamp" (燈 tō?) and "child" (子 ko?). Her surname means "my wife" (我妻 agatsuma?).
- She knows Yoshiteru can do a good job if he tried, so she hopes he can act maturely. She hopes to be a prosecutor in the future. Yoshiteru only managed to get into high school because Toko made sure he studied.
- After Yoshiteru saved her from being run over by a truck once before, Toko took care of her brother’s injuries until he was back in good health, showing love for Yoshiteru despite having little patience for his antics.