The main character of the series, Jiyu is a 14-year old junior high school girl attending a new school at the start of The Secret of the Lovely Eyepatch. She has a bright personality and a close relationship with her father. She is very well rounded which grabs the attention of the boys in her school and local area. Her nickname is Jubei, a reference to the famous Japanese swordman Yagyu Jubei. As Yagyu Jubei, Jiyu is described as a calculating young swordwoman with a completely different persona, although some of her true self is still shown. Whenever she defeats an enemy, she releases him/her from their hatred on Yagyu Jubei. Despite her appearance of a petite young high school girl, Jiyu does have some skills, one of these is the "Yagyu Shinkageryu Mutodori".
Jiyu first encountered Koinosuke Odago, who had been searching for a worthy successor for the Lovely Eyepatch. After her first transformation into Yagyu Jubei, Jiyu is targeted by the Ryujoji Yagyu clan, a school that has had a grudge on Yagyu Jubei. Since then, Jiyu has battled with the Ryujoji clan and their leader.
The second series starts a year later. Even though Jiyu has tried to forget the events of the first series, she still feels guilty over what happened to Koinosuke. She requests Sai quit being a ghostwriter and write her a love story under his own name. She meets and befriends Freesia Yagyu, a transfer student from Russia, and later encounters Koinosuke's child, Ayunosuke. At first, she refuses to wear the Eyepatch, but after being attacked by the Siberian Yagyu and Freesia, she picks up her sword once again.
After being slapped by Sai, Jiyu falls into a state of confusion, mistaking Mikage as her mother while not recognising Sai as her father. Later, both Mikage and Sai help her to regain her memories. Understanding her destiny, she provokes Freesia into an amazing duel and convinces her to stop her goal of vengeance, after which they are attacked by the spirit of Kita Retsusai. Together with Freesia, Jiyu defeats Retsusai, wiping him out of existence. She feels guilty over what has happened to Ayunosuke, but the last screen shot shows her reuniting with Ayunosuke.
Note: Jiyu's nickname Jubei if pronounced slowly is Jiyu-bei.
Sai is Jiyu's father and a ghostwriter of silly samurai dramas. He is often tormented by the memories of his wife, who died at home by Jiyu's side when he used to work in his office. After the incident, he promised to be a better father to Jiyu and subsequently started working at home. Despite his appearance, Sai is in fact talented, he taught Jubei the "Yagyu Shinkageryu Mutodori".
In the first series, Sai is shown as an hilarious character who often gets beaten up for being mistaken as Jiyu's stalker. He learns the truth about Jiyu after Mikage tells him. When Jiyu battled Taiko Daiyu, he lets him possess his own body and fight his daughter. However, Sai still wants to protect her, and aids her in defeating Taiko Daiyu. He is last seen crying after finding out that Mikage is married.
When the events of The Counter Attack of Siberian Yagyu take place, Sai instead of writing historical samurai novels, writes a romance novel under his own name at his daughter's request. However, when his old boss begs him to write a samurai novel, he skips his daughter's request. Later, Jiyu finds out about this and left home; Sai is depressed and tricked by Freesia, he slaps Jiyu the moment she returns which makes her fall into a state of confusion. He apologises to Jiyu and convinces her to fight again. After the incident, Sai stays home working under Mikage's supervision.
Freesia Yagyu is The daughter of Yagyu Jubei with a Siberian woman. As a child, Freesia witnessed her father's fight with Kita Ressai, during the fight, Freesia fell into the lake were her father and Ressai were fighting and was trapped inside a block of ice for 300 years until it melted. While Jiyu dons a Heart-shaped Eyepatch, Freesia makes a Spade-shaped Eyepatch and calls up her father's power to transform herself into what she calls the true Yagyu jubei the Second.
Freesia believes that she is the rightful owner of the Lovely Eyepatch, she came to Japan only to take it back from Jiyu. Freesia intends to make Jiyu suffer as she has suffered, she tricks Sai into believing that Jiyu left home becaues he lied to her about writing the romantic novel under his own name instead of continuing to ghostwrite and that he is a fake father. This makes him slap his own daughter the moment she returns home, putting Jiyu in a state of confusion. After being done with Jiyu's part, she plans to finish what her father could not, destroy the Siberian Yagyu.
While waiting for them, Freesia encounters Jiyu, who has regained her memories, the two rivals engage one another in a fantastic duel. Jiyu however, convinces Freesia to stop fighting as she is her friend. Freesia finally realizes her mistake and atones for this by fighting alongside Jiyu to defeat Kita Ressai. She is last seen visiting her father's grave.
A follower of Yagyu Jubei, he carries the task of searching for a worthy successor to his master. After 300 years, he met Jiyu in the modern day Japan. He tries hard to persuade her to wear the Eyepatch which she quickly refuses. He then takes up residence with the Nanohanas and builds his own Koinosuke's hut (doghouse) although Jiyu said he could sleep in the house he says that he doesn't want her to spoil him. He sometimes transforms into a 300-year old old man for not fulfilling his task. Despite his appearance, Koinosuke states that he has no fighting skills.
His life centers around the mission he was given by his former master and he struggles to find a new life after he Jiyu tells him. In the end, he is reunited and served his master in the afterlife.
Koinosuke appears briefly in the second series to support Jiyu and his child.
Koinosuke's only child, although having the appearance of a boy, Ayunosuke is actually a girl. Koinosuke entrusts her the Yagyu's successor task if he fails.
When Jiyu first blew the "Koinosuke Whistle", Ayunosuke appears in front of her eyes and gives her the Eyepatch, Jiyu quickly escapes and is chased by Ayunosuke. Since then, Ayunosuke has watched over Jiyu and often gets attacked by Freesia and questioned by Mikage. Eventually, she treats Jiyu's wounds and continues to convince her to wear the Eyepatch, but she refuses and says that she doesn't want to fight anymore; this makes Ayunosuke exhausted and transforms into a 300-year old body.
Later, she is revived after Jiyu wears the Eyepatch and witnesses her fight with Freesia. In the end, Ayunosuke is reunited with her father in the afterlife but she is seen at the last screen, sleeping in her father's doghouse.
One of the male characters who fell in love with Jiyu. He first met her when they both wander around the forest. Despite believing he is the second child, Shiro is in fact the first. He is shown as an enthusiastic young man at the first series. He tries to free Jiyu from burden of becoming Yagyu Jubei after found out about this, but fails. He challenges Jiyu to a duel and defeats her, however, Jiyu passes out. Shiro is attacked by Hajime, and is found by an old teacher. Then he duels with Hajime and free him from the 300-year old grudge of the Ryujoji school. While visiting his savior, it turns out that he became possessed by Taiko Daiyu's spirit. Later, he fights Jiyu and nearly kills her, but Shirou's self overcomes Taiko Daiyu's spirit (after seeing jiyus chest and realising that he can't stab her in between her two breasts) turns back to his own self.
In the second series, Shiro apparently has lost his fighting spirit (though this returns near the end of the series) and becomes much like an idiot. He joins Bantaro's gang, and often ends up playing their crazy games.
Nick name: Chief, skipper, Ban.
Bantaro is the leader of the Ruffians (unrefined) gang of three at Hontsuru Jr. High and heir to the 300 year running Sanbonmatsu sake brewery in Hontsuru city, but he isn't a bright character, in fact he is probrably the least intelligent of the three. Since the first day that he saw Jiyu riding her bike, he fell in love and being in love means that he would do anything to protect her.
Bantaro's role in The Secret of the Lovely Eyepatch is little, in fact, he protests that he became more unusable in every episodes. In The Counter Attack of Siberian Yagyu, together with Shiro, they formed a group known as The trio idiots + Shiro and open a campaign to protect Jiyu.
Trivia: The label on Bantaro's shirt and hat often shows his emotions and actions writing in Kanji.
The two monkey-like members of the Ruffians; Ozaru, the short one, and Kozaru, the taller one both seem to be a little more intelligent than their leader. They are not shy when it comes to criticizing their leaders. In fact, they seem to do it very often. However, when their leader becomes hurt, they are usually the first ones to react.
Shoko, whose nickname is Maro, is also a new student at Jiyu's school. She is a cheerful girl who usually recommends that the three new students form a group call the "New Student Lovelies" which is often declined by Sachi. She seems to like older men and has a crush on Jiyu's father, this however, is not present in the second series.
Sachi is also a new transferred student like Jiyu. She never seems to have much to say nor wants to do anything, and often declines the formation of the "New Student Lovelies", this makes Shoko say that she is no fun. Sachi appears to have some romantic interest with Kozaru.
Once an assassin sent by the Ryujoji clan to assassinate Jiyu . After being defeated and saved by Jiyu, she devotes herself to protect her. She also looks strikingly similar to Jiyu's mother; this causes some confusion for Sai, who misses his wife and hasn't felt love in a long time, so he falls on Mikage. In The Counter Attack of Siberian Yagyu, Mikage still strives to protect Jiyu while working as Sai's editer.
Once Daigo Ryujoji, a samurai who lost to Yagyu Jubei, after Jubei passed away, all his hatred and vengeance became the spirit of Taiko Daiyu. Taiko Daiyu survives for 300 years only to see the resurrection of Jubei and to defeat him. Taiko Daiyu has an ability to assimilate people and then make their body and skills his own for the using. He tried to take over Shiro's father, Amon, but was unsuccessful. Instead of this, he forces Amon to give up his first child (Hajime) and raise him to be the successor of the Ryujoji.
Taiko Daiyu takes the form of a teacher at Hontsuru Jr. High. He treats Shiro's wounds, this makes Shiro thanking him. On the other hand, Taiko Daiyu takes over Shiro's body to finish Yagyu Jubei for good. He nearly kills Jiyu, but is foiled by Shiro's spirit, so he possesses Sai instead. Following their fight, he was destroyed by Yagyu Jubei the Second.
Shiro's twin brother, and also the head of the Ryujoji school. Despite this, Hajime is in fact the second child, Hajime knows this and still accepts his role.
At the beginning of the series, he appears as a shadow figure with only his eyes are shown. In addition to achieve his goal, he request his brother to join their ranks, but is refused. He then lures Shiro to duel with Jiyu only to take the Lovely Eyepatch, but since he does not know its secret, he abducts Jiyu as well. This makes Shiro fight him but Jiyu steps in and stops their fight Jiyu transforms into Yagyu Jubei the second and provokes him to fight but in one strike Jubei frees him from the 300-year old grudge. Hajime then is recruited to join the Ruffians.
Hajime only makes some briefly appearance in the second series. He has dyed his hair green and also became a hard music fan.
Mikage's husband, his family name has never been given. Like his wife, Tenryo was also defeated by Jubei the Second and devotes himself to fight for the defence of Jiyu. He became a hewer in The Counter Attack of Siberian Yagyu.
The leader of the kita Yagyu later known as Siberian Yagyu. After driven out of Japan, Kita Retsusai and his son resides in Siberia. When he caught up Yagyu Jubei, mistakenly think that he was sent to assassinate him, Kita Retsusai provoke a duel between him and Jubei. At the heat of their battle, Kita Retsusai unleashed his ultimate technique and broke through the ice, drowning Jubei's wife and daughter. He was also fell off and vanished in the river froze, what happened to him afterward is unknown.
Three hundred years later, Kita Retsusai's spirit is resurrected when Kita Furo called up for his powers, and is trapped inside a puppet figure of the Siberian Yagyu. He reappears to end his battle with Yagyu Jubei 300 years ago, now fights with his two successor. He appears in a form of a giant ice monster is able to reconstitute himself so quickly that Felicia and Jubei have no choice but to fight together as one. Following their duel, he is defeated and finally made peace with Yagyu Jubei.
Kita Furo was once an admirer of Yagyu Jubei, but due to the destruction of their clan, he has changed his heart. Furo lost his right eye from birth.
For 300 years, he carries his father's grudge and swore to make Jubei pay for banishing his clan. He encounters both Jiyu and Freesia, mistakenly thinks that there are two Yagyu Jubei the Seconds, Furo goes on trainning, eventually he inherits his father's strength and technique.
He returns to find out that Jiyu in a state of confusion. He tells her that he wants a rematch after finishing Freesia. He duels Freesia but still losses, his body later is trapped inside his father's re-incarnation , an ice monster and is saved by Jiyu. In the end, Furo is taken care by White Tiger Nizaemon and becomes a police officer.
The other members of the Siberian Yagyu consist of Kita Ressai's five most trusted assistants (their names probably changed after living in Siberia) and some henchmen. Despite their elderly age, they still have some fighting skills left, but Freesia says that they are all eyesore, and they sometimes show their cowardliness.
At the beginning of the series, they and Kita Furo team up (of sort) to defeat Jiyu. They kidnap Freesia and force Jiyu to withdraw, the plan however ended in failure with the defeat of Nizaemon. They try to return to Siberia when Freesia states that she will kill them, but also unsuccessful. In the end, the Siberian Yagyu (with the exception of Nizaemon who had been defeated) follow their master to the afterlife.
The legendary Japan swordman, Jubei appears briefly in the first series as an elderly man; in the second, he is described as a middle-aged man and also given a little sense of humour.
The second series reveals most of his past, he was sent to assassinate Kita Ressai and the remaining Northern Yagyu, though he did not wish to carry out the job. During his time in Siberia, he fell in love and had a daughter named Freesia. He later caught up with Kita Ressai who provoked him into a duel and drowned his wife and daughter, and Jubei screamed in agony.
Several years later, Jubei's father decided to get rid of the other yagyu styles in the land. This caused some people to be very upset and in attempts to prove they were better, they challenged Jubei and all lost. Thus, the Ryujoji's grudge was born. Jubei after defeating Daigo Ryujoji, passed away and entrusted his disciple Koinosuke the Lovely Eyepatch.
Otome is a girl who has a serious crush on Shiro. Her aunt runs the Shirahatamaru school where she and her friends Kocho and Ocho attend. Although she shows up frequently in the show, she really doesn't do anything that impacts the plot. Kocho and Ocho always follow Otome everywhere she goes and tries to give her encouraging words.
She is a nurse at Hontsuru Jr. High and cured Bantaro after he as attacked and tried to diagnose Jiyu. Her name has never been given.
He is Sai's boss at the time that Makoto died. He scolded Sai for talking to his daughter at work. He begged Sai to write for him in the second series.
He is the schoolmaster of Hontsuru Jr. High and is also one of Hajime's henchmen. He's not too bright and eventually gives the eye-patch to Jiyu accidentally.