Kayo

Appearance
Kayo has light brown skin, full lips and expressive brown eyes. She also has brown hair which she wears in the elaborately laquered style of the Edo period. Her clothing consisted of a yellow kimono with a purple obi.

Personality
Kayo is a hyperactive girl around the age of nineteen to twenty and is shown to get easily excited or scared. She can also become almost childish. She has a strong desire to become married and have children; however her worst fear is giving birth to a disfigured child. She seems to be attracted to the Medicine Seller, as she is the first person to befriend him and is later seen blushing when he volunteers to accompany her to the kitchen. She thinks that old men are "perverted" and "disgusting".

Ayakashi: Samurai Horror Tales
Kayo first appears in the three episode "Bakeneko" arc in Samurai Horror Tales as a servant girl working for a samurai family that is slowly drowning in debt. She meets the Medicine Seller while preparing for a wedding, and after being shown several marriage charms she quickly becomes his friend, willingly giving him information about the family she works for, even the fact that they are suffering from increasing financial problems as the result of the head of the household's wife's whims and desires. The samurai family also hope to use their daughter's marriage to pay off their debts. Suddenly Kayo is frightened by the presence of a rat, bringing the Medicine Seller's attention to several rat traps lying about in the kitchen. Kayo explains that her employers don't use cats for their rat problem when Sato, a court lady, unexpectedly arrives and scolds her for neglecting her work, and orders her to fetch water. After Kayo leaves, the Medicine Seller questions Sato about the absence of cats in the household, to her surprise.

Sometime after Lady Mao's unexpected death, Kayo is ordered by Sato to light some candles around the body of the deceased, but she feels so unnerved about going alone that a sympathetic samurai, Odajima, offers to join her. Kayo asks the grandfather of the current head if Mao's death has anything to do with demonic spirits, and is told no. Kayo is scared when, as they pray, Odajima hears something and is about to draw his sword. Even more unsettling is when everyone suspects the noise sounds like the meowing of a cat. Odajima and Kayo arrive back, but things turn frightening when the Medicine Seller, who has been tied up on suspicion for poisoning Mao, notices blood dripping from Odajima's robes and kicks the samurai, knocking him back and revealing the dead body of an old family retainer who had gone missing shortly after leaving the house. Kayo, along with Sato, becomes very terrified at the sight and screams in distress.

The Medicine Seller frees himself from his bonds and throws bunches of ofuda (magical charms made out of paper designed to ward against evil spirits) all over the rooms of the house, further terrifying everyone present. Kayo reveals the Medicine Seller that Lady Mao and the grandfather are in the back room, so he goes there and plants several ofuda there as well, despite Odajima's protests. They immediately hear the sounds of scratching claws against wood, followed by a loud growling that causes a tremor that goes unnoticed by the people outside the house. Odajima, not believing the purpose of the ofuda, tries to go outside and manages to catch a glimpse of what possibly could be a monster. The Medicine Seller reveals to him, Kayo, and everyone present that the cause of the mysterious deaths was a bakeneko spirit, or "goblin cat", further confirmed by the presence of cat fur on Odajimi's robes. He demands to hear "everything" from the people listening to him.

Kayo is later ordered by Sato to get more sake when the brother of the head of house, Yoshikuni, drinks it all, but the possibility of demonic spirits lurking in the kitchen unnerves her so much that Odajima and the Medicine Seller both go with her, to accompany her and to get some salt, respectively. While at the kitchen, Kayo slips and discovers spilled oil on the floor. She is handed the sake kettle she was looking for, and goes back to help the Medicine Seller set up barriers of salt and magical scales to detect the bakeneko. But when Odajima derides the Medicine Seller for having a "useless" weapon, and after the Medicine Seller explains the "Mononoke", Kayo is given incentive to reveal that Sato has been secretly buying cats with her own money, but they always disappeared. The brother of the head of house cruelly reveals that the cats have been used to test the sharpness of their katanas, which horrifies Kayo and leads to an outside argument that is diffused by the grandfather of the head, not wanting anyone to displease his dead granddaughter.

While waiting for something to happen, Kayo asks for the current time and is told by Odajima that it could be past midnight. Suddenly she and Odajima both hear the ringing of bells, which is triggered by the approaching bakeneko as it searches for a way inside the house, but cannot enter because of the barriers. As the Medicine Seller is occupied, the wife of the current head of house wakes up from a fainting spell and immediately grieves at the sight of her dead daughter; the strong emotions present give the bakeneko enough power to destroy the barriers and kill two people. The Medicine Seller makes a futile attempt to ward off the bakeneko, but is saved by Kayo, who succeeds in driving the spirit away by making it eat a full jar of salt.

The Medicine Seller questions the remaining people about the existence of "Tamaki", a young lady wearing white who is mentioned during the wife's period of hysterical grief. As the ofuda barriers dissolve, the remaining people escape to the basement by means of a secret passageway. There, Odajima and Kayo discover a white wedding kimono hanging on a pedistal, when everyone hears Sato suffering from a breakdown on the way down the stairs. To their fright, both Odajima and Kayo recognize the kimono as the one "Tamaki" was wearing, and immediately the kimono is burnt up as the bakeneko surrounds the basement. The Medicine Seller discovers that the cause behind the bakeneko's truth is the grandfather. The grandfather reveals that twenty-five years ago, he had kidnapped a young maiden for his own pleasure; at first the maiden willingly stayed with him, but when she requested to go back home, the grandfather in his rage beat her and imprisoned her in the house's basement.

Sato's madness further empowers the bakeneko, and soon a struggle between it and the Medicine Seller begins. Odajima and Kayo try to run with Sato and the grandfather to the safety of the basement, but then Sato starts trying to choke Kayo to death. Odajima tries to help Kayo but is stopped by the grandfather, who then tries to break his neck for protecting a lowly house servant. In his desperation to save Kayo, Odajima disobeys his master and begs the Medicine Seller to "do something!" The Medicine Seller tries to unsheath his sword. But without the reasons of the bakeneko, the attempt fails and the bakeneko breaks through, injuring him and killing Sato, the head of house and the other samurai employed along with Odajima by devouring them. Odajima, the grandfather, and Kayo are saved by the magical barriers put on them, but are forced to watch as the bakeneko spreads the remains of its victims all over the walls, traumatizing Kayo, who is in full view of it. Kayo and Odajima are also brought, along with the Medicine Seller, by the bakeneko to see its past and how it came to be, and by serving as witnesses more is revealed:

After being imprisoned, the kidnapped maiden, "Tamaki", is revealed to be raped and abused at the whims of the grandfather. The only friend she had as company was a dark gray cat that had been in hiding with her. As time passed, the cat grew and grew on the maiden's food, while Tamaki herself suffered from more abuse and from starvation at her own expense; despite that, she loved her friend very much and took great risks in keeping the cat's existence secret. One day, the grandfather's oldest son, Yoshikuni, arrived and raped Tamaki, but was discovered. The grandfather misinterpreted it as seduction on Tamaki's part and beat her until she died. The cat tried to protect her but failed, and was forced to escape; the great regret it harbored later in life from this incident eventually transformed the cat into the bakeneko it is today. As for Tamaki, her body was discarded by the other samurai in an outside well.

Feeling sorry for the bakeneko, the Medicine Seller mercifully exorcises the spirit of its sorrow and vengeance, transforming it back into a normal cat and bringing it peace in killing it. Kayo and Odajima, the only people to actually retain their innocence, decide to lay the cat to rest next to Tamaki's grave, both out of sympathy for it and to make up for the wrongdoings of the family that hired them. After that, Odajima, the Medicine Seller, and Kayo part from the now empty household (except for the grandfather, who had been left alone to forever remember his past misdeeds) on good terms, with Kayo returning to her parents' home, having had no desire to work as a servant anymore since the discovery of her employers' past.

Mononoke
She met Kusuriuri again in a ship trip, trying to help him to deal with the demon, since they met previously in the episodes from Ayakashi. Also: A young waitress named Chiyo who bears a striking resemblance to Kayo appears in episode 10 of Mononoke. She is strongly implied to be a reincarnation of Kayo, having a similar personality and sharing the same voice actress.