Yume is a girl with long hair that reach to her waist. She has light grey eyes and light pink hair fading into violet at the tips. She also ties her hair into a large ponytail.
She is often seen wearing Elite Guard's uniform with white stockings and black high heels.
Yume shows a childish personality appropriate for her age and is a battle maniac, flipping like a switch into a mode where she becomes unstoppable. Because of this, she is treated with utmost care by those around her, and is often forbidden from joining any operations, which leaves her dissatisfied.
Suzuka describes her as "a girl who does not know the word 'restraint'".
Despite this, she isn't evil, she doesn't kill, and mostly wants to live her life to fullest, fighting great battles and making people remember her existence and her greatness.
Yume was considered a prodigy among Toji of her age. Despite being a young Toji, she immediately obtained a compatible okatana, and was highly praised for her swordsmanship skills. Eventually, she enrolled Ayanokouji Martial Arts School.
However, as a student of Ayanokouji, an unknown disease struck Yume, causing her to become bedridden in a hospital for a long time. As she became emaciated by her condition, her parents stopped visiting.
One day, Yukari Origami and the president of Ayanokouji Martial Arts School, Yuzuki Souraku visited her, bringing a life changing choice—"Will you die in obscurity like this and vanish from everyone's memory? Or will you shine brightly for a moment and sear that brightness into the memories of all those who have forsaken you?"—and showing her a vial of noro. It can be assumed that Yume accepted the noro vial and eventually joined the Origami Family Elite Guard.
Because of her tendencies, Yume was often seen in the sidelines while her fellow Elite Guards assumed more active duties. She accompanied Maki Shidou and Suzuka Konohana during the National Swordsmanship Tournament, and was forced to spectate as Maki officiated the event. It was only during the interrupted decisive match where Yume was able to sneak out and attempt to bring down Kanami and Hiyori, who were escaping after a failed attack against the head of the Origami Family.
During the investigation of the failed assassination attempt on Yukari Origami, Yume once drew her sword at Kanami's teammate Mai Yanase in an aggressive gesture, although Minoseki Academy's president Ema Hashima was able to stop the confrontation from escalating. Nonetheless, as a more intensive operation was called against Kanami and Hiyori, Yume was once again prevented from taking any direct action. Eventually, Yume would attempt to "play with" Yukari by attacking her, but it would fail against the Origami head's superior swordsmanship skill. However, Yukari assured Yume that she would eventually have her "time to play" and asked her to be patient.
Yume finally found the opportunity when Sayaka Itomi of Renpu Girls' School escaped from a procedure that would inject a vial of noro into her bloodstream. Somehow seeing herself in Sayaka, Yume began a pursuit on the fugitive from Renpu, and she would confront Sayaka and Mai in a two-on-one fight. Ultimately, President Yukina Takatsu of Renpu intervened, leaving the fight without a conclusion.
Yume would also be deployed on the base of the anti-Origami group Mokusa immediately after Yukari managed to determine its location through a noro vial stolen by the group during an operation against Kanami and Yukari in Ebisu. With units of the Special Ritual Riot Squad restraining any civilians, Yume singlehandedly took care of the combatants from Osafune Girls' Academy, but was unable to catch the leaders of the group. Although the prolonged fight against the students of Osafune weakened her to the point of coughing blood the night after the battle, Yume was able to respond to the reemergence of a Great Aradama a few hours later. Yume would eventually travel by helicopter back to Kamakura after reports of several S-Equipment pods broke out from within the headquarters of the Special Sword Administration Bureau.
Still remembering how Kanami dealt with her attacks during their first clash, Yume immediately went for Kanami and the two exchanged blows against each other inside the main temple of the Origami estate. However, due to the intervention of Kaoru Mashiko and Ellen Kohagura, Yume was separated from her desired enemy. For a while, Yume struggled to keep up with Kaoru and Ellen's teamwork, but as the stamina of the duo started weakening, Yume was able to bring them down, even without using the power of the noro injected into her bloodstream. However, the tense fight against the pair from Osafune severely exhausted her, and as she hurried to reach the inner temple, her health rapidly broke down and she continued coughing blood along the way. Yume soon became too weak to finish the journey towards the inner temple and sat down a nearby tree, contemplating on her imminent demise. She passed away some time after.
Maki and Suzuka later discovered Yume's corpse after their defeat in the hands of Kanami Etou and Hiyori Juujou. After taking Yume's okatana, Suzuka urged that Yume's remains must be dealt with or else the Aradama in her bloodstream would take control.
Master Swordsmanship: Yume was extremely skilled in kenjutsu, as proven by her status as a prodigy at a young age. She has shown her skills in facing one or multiple enemies at the same time using both speed and accuracy, hitting enemies at vital areas to gain victory as the least amount of time. In fact, her swordsmanship skills far exceeded that of fellow Elite Guard Maki Shidou, a two-time National Swordsmanship Tournament champion. She was also capable of overwhelming Mai and keeping up with Sayaka for a while before being outclassed by both of them. Although she preferred to end fights in a single hit, when faced with an "interesting" opponent, she could deliberately stall a fight by hitting an enemy in non-vital areas, causing the opponent to be worn down through the mental stress caused by Utsushi usage.
- Swordsmanship Style: Ten'nen Rishin-Ryu (天然理心流?) - A style whose strength manifests more in actual combat than in the use of shinai matches. This style adopts kenpo techniques compiled during the Shinsengumi period, and stresses the importance of confirming kills.
Immense Speed: She possessed great speed and swiftness, capable of keeping up with Sayaka, a fast Toji herself. She managed to defeat five Toji from Renpu simultaneously in the span of a few seconds.
Average Stamina: She had an average amount of stamina due to her illness she couldn't fight for extended periods of time.
Utsushi Proficiency: As a Toji of Elite Guard, she could maintain utsushi for a very long time and was able to use it multiple times with ease.
Noro Empowerment: As member of the Elite Guard, Yume gained access to the ability to empower oneself using noro. When unleashing this power, a red aura emanated from Yume's body. However, due to Yume's conviction, she refuses to draw out this power, even to the point of hitting her own head to surpress and restrain it.
Okatana: Nikkari Ao'e (ニッカリ青江?) - An altered tachi whose length is shortened to that of a wakizashi. According to folklore, the name "nikkari" came from the laugh of the ghost of a woman that this sword slayed. Its current status is unknown, most likely it is being returned back to responsible organization in charge of keeping this okatana.
- Her birthday coincides with the celebration of Hinamatsuri.
- Yume's biography has several similarities to that of another famous practitioner of the Ten'nen Rishin-Ryu, Sōji Okita. Aside from their usage of the Ten'nen Rishin-Ryu, both are known for being prodigies at a young age, and possibly both of them suffer from tuberculosis. Yume also uses the Sandanzuki (lit., "Three-Piece Thrust"), a technique often associated with Okita.