Kasumi has long light colored hair that extends past her shoulders with the hair in front of her forehead is cut diagonally and some that are the side that is cut just above her chin. She also has dark colored triangle shape eyebrows.
Kasumi wears black long sleeved jacket over a light colored button down shirt and a black tie, black pants, black socks, black shoes, and a belt that she uses to hold her sword.
While training, Kasumi has her hair tied in a ponytail and wears a dark colored track suit.
Kasumi is a hard-working, restrained and considerate pacifist. She is also a big fan of Satoru Gojo.
Kasumi comes from a poor family and has two younger brothers.
Cursed Training Arc
Kasumi accompanies principal Yoshinobu, as his secretary, to a meeting with principal Masamichi. While Yoshinobu talks with Gojo, as they wait for Masamichi, Kasumi thinks about how cool Gojo is. Kasumi is shocked when Gojo tells them that Masamichi will arrive in 2 hour, as he is leaving. When Yoshinobu tells her to go get his some tea, Kasumi heads out while hoping to get a picture with Gojo.
Kyoto Goodwill Event Arc
On the day of the Kyoto Goodwill Event, Kasumi accompanies the Kyoto students and faculty to the Tokyo college. After encountering the Tokyo students, Kasumi is glad of Gojo's arrival and is even given a souvenir from his trip. Afterwards, Kasumi attends a meet with the other Kyoto student and principal Yoshinobu. Yoshinobu tells them to kill Sukuna's host, Yuji, during the event, which Kasumi thinks about how she doesn't want to. After Aoi and Yoshinobu leave, Kasumi talks with the other student one how they should handle the event.
When the event starts, Kasumi and the others manage to locate Yuji and surround him. As Mai draws Yuji to her, Kasumi goes to attack him but Yuji manages to evade her. As Aoi forces the Kyoto students to retreat from killing Yuji, Kasumi is glad about that. As Kasumi retreat with Noritoshi, both of them encounter Megumi and Maki.
As Kasumi takes on Maki, Maki wonders why she seperated from Noritoshi. Kasumi tells Maki that she wants to use this event in order to get promoted and help out her family. After talking, Kasumi and Maki continue to fight with neither holding back. As Kasumi fight Maki, she notices that Maki is stronger then what Mai had told her. As Kasumi is put on the defensive by Maki's attacks, she decides to take a stance in order to counter. When Maki breaks her weapon, Miwa wonder why she did that. As Maki throws a part of her broken weapon at Kasumi, Kasumi easily blocks it but notices that Maki had thrown a kunai. As Maki manages to get close to Kasumi, Kasumi defend herself against Maki. Kasumi notices that her feet had moved and plans to get back into positon, but Maki tosses Kasumi and even disarms her. Kasumi then asks for her sword back but Maki doesn't give it and leaves.
As Kasumi wonders what to do, she suddenly gets a call from Mechamaru. As she answers the phone, Toge is on the other side and puts her to sleep. When intruders invade the event, Kasumi is still asleep.
After the invaders have been dealt with, Kasumi attends a meeting and agrees with the others to continue the event. One the second day of the event, Kasumi plays baseball with the others. After the event is finished, Kasumi head back to Kyoto along with the students and faculty.
Shibuya Incident Arc
Sometime later, Kasumi informs Mechamaru that their notebooks are due that day. After telling Kasumi where his notebook is and that he will be asleep for a bit, Kasumi pokes Mechamaru and wonders were his real body is at.
Later, Kasumi talks with Mechamaru and informs him that she wishes to get closer to him along with meeting with him in person one day.
Currently Kasumi has the strength of a 3rd Grade Shaman.
Cursed Power and Forms
Kasumi's cursed power is Shinkageryu: New Shadow Style - Simple Domain (otherwise known as Shinkage Clan: New Shadow Style). This technique combines Kasumi's swordsmanship with her cursed power. After taking a stance, Kasumi will attack anyone to comes within 2.21 meters of her. If both her feet leave their position from when the spell it used, the technique ends. The blade of the sword is covered with cursed energy, and allows for the sword to be drawn even faster. This technique is the fastest of the Shinkageryu.
- Kasumi ranked 11th place in the manga's 1st Character Popularity Poll with 4,923 votes.