She is voiced by Ai Kayano in the Japanese version of the anime, while in the English version she is voiced by Krishna Smitha in season 2 and Amanda Lee in season 3.
Itsuwa is an average Japanese teenage girl with long black hair (purple in visual medium) that goes all the way down to her shoulders and is a bobcut with short fringes. She also appearently has double eyelids which Touma notices when first meeting her. She also has light brown eyes. Itsuwa typically wears a pink tangtop with white sweatpants that have been cut short as her average attire. During the incident in Avignon, France, her cloths got soaked and she was forced to wear skimpy clothing because there was nothing else to wear. Despite driving boats and piloting helicopters, she is around Touma's age of 16 and is too young to drink alchohol.
Itsuwa comes off as a kind and warm-hearted individual. She is very humble and sweat towards people, especially Touma. She is charming in both appearance and personality as documented by her fellow comrades. Itsuwa is described as a girl in love and has romantic feelings for Touma which he has yet to notice but she has caught his attention as she is never hostile towards Touma and is a fresh new face from other girls like Mikoto Misaka and others who demonstrate levels of hostility on many occasions. During battle, she is seen facing the enemy without hesitation and is a key ally and is seen fighting close to Touma whenever the two are together during missions. Itsuwa is also very emotional and it can harm her skills in battle as she got depressed when she was unable to save Touma from Acqua of the Back from getting beaten up. Overall, Itsuwa is a kind-hearted and caring person with charm and is very humble but also very emotional and attached to Touma.
- Amakusa-Style Combat: Like all members of the Amakusa Church, Itsuwa is skilled in their unique combat skills and techniques. It is mostly a combination of varius abilities stemming from different cultures and backgrounds.
- Friuli Spear: Itsuwa's primary weapon is her Friuli Spear. It is 7 feet long and can take down multiple enemies at once.
- Saint Destroyer: The Saint Destroyer is the Amakusa's trump card and can take down an enemy Saint-class magician in combat when encountered. To activate it however, all of the Amakusa members must be united in one group and activate it all at once. Itsuwa is the only known member who can use it and will fire it once all of the other member have been able to contribute to its affect.
- Cooking: Itsuwa's an expert cook that even managed to impress Maika Tsuchimikado.