Kiyoko has light blue wrinkled skin; light hazel brown eyes; pink lips; long white braids tied by yellow bows on the opposite sides of her head; and wears a pink nightgown. Despite having the body of a child, she has premature aging which makes her appear between her late 40's and early 50's. Due to her physical frailty, she is often seen lying in bed.
In the Espers' flashback, Kiyoko had fair yet healthy skin; light brown hair; and she wore a pink, short-sleeved dress. She also looked younger, as the flashback took place sometime before the government's psychic experiments began.
Kiyoko has a kind and gentle personality, and due to her powers she is very wise and perceptive. She is akin to a spiritual leader, giving people advice and guiding them towards their destinies. She is also very concerned for the people around her and sees Tetsuo Shima as a dangerous threat, even trying to assassinate him at one point to prevent him from causing untold destruction. She tends to speak in a cryptic manner due to the vague nature of her precognitive powers, forcing people to fill in the gaps themselves.
Despite her maturity, Kiyoko's mind is akin to that of an extremely sheltered child. Because of her isolated life, she is unfamiliar with a lot of things from the outside world, and is shown to be extremely terrified by the sight of blood. She also carries a doll, which bears the appearance of a young girl, while she sleeps. Eventually, in the end she and her fellow Espers gather the courage to escape the government facilities where they have lived all their lives, and travel to the Olympic Stadium to stop Tetsuo.
Kiyoko is very close friends with Takashi and Masaru, to the point of acting motherly towards them at times. Because of her physical frailty, she relies on them for support and protection. Although Masaru often takes charge of the group, it is Kiyoko who has a final say in the Espers' decisions. She is also a good friend of Akira, expressing joy when Akira answers the Espers' psychic call for help and comes back to Earth in a spiritual form.
Judging from the amiable interactions with Colonel Shikishima, Kiyoko seems to be a close friend of his, their relationship being almost like father and daughter. Most of his decisions in the government rely on Kiyoko's future prophecies. Towards the end, after Akira's spirit produces a second psychic explosion that destroys Neo-Tokyo to absorb a mutated Tetsuo, Kiyoko teleports the Colonel to the city's outskirts and tells him to hide in a road tunnel, knowing the man will be protected from the blast.
Kiyoko was one of a large group of young children who were taken in by the government of the original Tokyo to participate in a secret parapsychology project that studied the development of psychic powers, presumably for military or political reasons. Since no mention was made of her parents, it was implied that Kiyoko was an orphan.
During her time as a psychic test subject, Kiyoko befriended three boys - Takashi, Masaru, and Akira. Out of all the children taken in by the government, Kiyoko and her friends were the only ones to survive the government's testing long enough to gain powerful psychic abilities. One day, Akira's abilities grew too strong to be controlled, resulting in the accidental creation of a psychic explosion that utterly obliterated Tokyo.
After the founding of Neo-Tokyo, Kiyoko, Masaru, and Takashi were put in prolonged isolation to hide information about the project and to prevent them from becoming another Akira, kept on a routine feeding of drugs that suppressed their psychic powers. This led to premature aging and the development of physical handicaps; Kiyoko eventually became so weak that she had to remain in bed, kept alive by medicine and life support systems.
Shortly after Tetsuo Shima was revealed to be a psychic and was taken in by the government as their latest test subject, Kiyoko had a prophetic dream about Neo-Tokyo's destruction and Akira's spiritual return. She relayed her vision to the Colonel during his visit to the Nursery while she was awake. Kiyoko also warns the Colonel about Tetsuo, whom she believes will be involved in Neo-Tokyo's destruction, before falling asleep. Kiyoko's predictions prompts the Colonel to visit the Olympic Stadium where Akira's remains were stored in a Cryogenic Containment Unit. He gives Doctor Onishi, a scientist, the order to kill Tetsuo the moment the teenager's powers grew out of control.
Kiyoko later teams up with Takashi and Masaru in an attempt to psychically assassinate Tetsuo before he becomes a threat to Neo-Tokyo. Using the Nursery's toys to disguise themselves as a rabbit, a bear, and a toy car respectively, they invade Tetsuo's hospital room with the intent to kill. During the attack, Tetsuo accidentally steps on a glass cup and cuts himself in the foot, shedding blood. The Espers, terrified at the sight of Tetsuo's blood, are forced to retreat, revealing themselves to Tetsuo in the process.
Enraged at the attempt on his life, Tetsuo goes to the Nursery to exact his revenge. Using Takashi and Masaru as her mouthpieces, Kiyoko tries to convince Tetsuo to stand down.
Kiyoko is gifted with precognitive powers that allow her to see into the future. Every time she makes a prediction, it always comes true. Her visions tend to come to her while she's sleeping.
She has the ability of teleportation, which allows her to move people, objects, or herself to faraway destinations without physical travel. She once used this on Colonel Shikishima, teleporting him to the edge of Neo-Tokyo to protect him from the city's destruction.
She can psychically possess people and channel her powers and thoughts through them. In later portions of the animated movie, Kiyoko used Kei, a psychic medium, to do things she could not, such as communicating with others beyond psychic range and battling a rampaging Tetsuo.
Kiyoko is shown to have telepathic powers which she used a few times to also communicate with others. She is also assumed to have psychokinetic abilities as well since she was able to take on the form of a giant pink rabbit by psychically covering herself with children's toys like a full exoskeleton, and float unaided during Tetsuo's destruction of the Nursery. She also freed Kei and Kaneda after they were imprisoned by using her psychokinesis to unlock their cell door.