Touko was a white-skinned girl with long black hair and an expressionless face, her tongue was slightly divided in two,
Her wardrobe was limited to a type of uniform/full black suit and only highlighting a long tie.
Touko was first shown to be a callous, murderous and destructive girl as she without care for her surrounding used her stick's explosive power to try to kill Kayo causing large-scale damage to her surroundings as a result.
She was also shown to be a cautious and calculating girl, as she first stalked and followed Kayo in order to learn the mechanics of her stick(Compact Mirror) power, gleaning its weak spots and its strong points before taking any action,showing that she at least puts heavy value in her own well being first.
She's also shown to be a caring sister as she desired to find a healing stick to heal her brother's severe burns and later expressed that she wanted him to keep living despite his desire to die, because their parents gave their life to save him, she showed worry for Sakura Sakaki when she does reckless actions, and later felt that she could trust Kayo Komura enough to reveal her reasons for being a Magical Girls and later made a promise together that if she died, Kayo would find a Healing Stick to help her brother recover.and later when she was killed, Kayo was greatly distraught over her death, crying and grieving for her.
Despite these positive traits she's admitted that she wants to hunt down who ever burned down her house and "Bury them" which shows that she has a vengeful side to herself too.
One day, when Touko was walking home, she saw her house in flames, she immediately panicked, but she was too scared to do anything. Once the fire stopped, she found out that her parents died trying to protect her younger brother where she fell into despair and she soon met A, who made her a magical girl.
Touko's conductor's baton was given to her by "A" it being one of the most destructive Sticks to date, as it has the power to cause whatever it is pointed at to explode. When she activate her stick her eyes get the Infinity sign within them, and her hair becomes longer and the tips changes color, she seems to bleed from her forehead when she uses her stick,
- The name Touko means "winter" (冬) (tou) and "child" (子) (ko).
- Touko's surname Arareya means "hail" (霰) (arare) and "arrow" (矢) (ya).
- Touko made her debut anime appearance on Episode 6, although it was a cameo.
- She was one of the many girls who appeared in the photographs.
- Touko and Explode M/Ribs, a character in Mahou Shoujo of the End, have one thing in common where it is being a magical girl who can manipulate the explosion ability.
- Hitomiko Yonekawa was blown up and killed by the left half of the face to someone who received a stick from A, but it is unknown if Touko committed this crime or not.