Rio Kizaki
Kanji 木崎リオ
Rōmaji Kizaki Rio
Alias Catgirl Rio
Personal Characteristics
Gender Female
Side Good
Family Shouichirou Kizaki (father)
Orie Kizaki (mother-deceased)
Professional Characteristics
Power(s) Highly Trained Close-Quarters Combat
Advanced Gadgets
Occupation Hero
High School Student
Affiliation Hero Association (directly sponsored by her father)
Andou Electronics (representative)
First Appearance
Manga Chapter 1
The Birth of Smallest Hero

Rio Kizaki (木崎リオ, Kizaki Rio) is a 2nd year student of the same school as Shuto Katsuragi. She is the daughter of Shouichirou Kizaki, the President of the Japan Hero's Association. Like Shuto, she is an aspiring hero. However she later achieves her dream and becomes Catgirl Rio for Andou Electronics.



Rio's Hero Mode

Rio has long dark hair, which she keeps up with two orange strings. She has a variety of outfits she has worn throughout the series. She usually wears a school uniform with a really short mini-skirt, which makes her thong visible at times, especially when she uses her wrestling moves. However, when training she prefers to wear a t-shirt and cut-off shorts with fingerless gloves, and when she went to the Hero Party she was dressed one piece white dress.

Rio has a very small and thin body, which causes many of the characters to look down on her as nothing more than a little kid.  However, her petite appearance belies her true strength and abilities, as she is shown to be one of the most physically powerful characters in the series.

In her Hero Mode of Catgirl Rio, she wears an armored dress/skirt ensemble with a fancy belt, jet pack, wrist gauntlets and stylized boots. She has two robotic cat ears and retractable claws, thereby adding to the cat girl theme. However despite the abilities these give her, she is greatly embarrassed by the outfit and the actions she must do to activate the abilities.


She greatly believes in the concept of Justice and being a Hero, what she one day wishes to be despite the fact her father initially would not give her a license. She will jump at the call towards any threat she picks up on her communicator or go into a burning building to rescue her friend. Her desire to become a hero stems from the fact that she was unable to do anything when her mother perished in front of her.

Her belief in Justice is so strong, she even shows disgust towards the Hero Association covering up the activities of G9 working with criminals just to protect the Association's image. Though she is happy about finally becoming a Hero, she does not like the fact that she must do silly cat moves and speeches in order to transform and activate her weaponry. However, since she does represent Andou Electronics and is now a Commercial Hero, she is bound to the rules set by her weapons-maker and tactical adviser Andou Hironobu.


After watching the explosion which killed her mother, (incidentally it was the same time in which Shuto was greatly injured and rescued by Shiningman), Rio began wanting to be a hero so that others would not suffer the pain of losing loved ones. She would later undergo intense physical training to the point the army was already considering recruiting her despite her age to prepare herself once she became a hero, regardless of the fact that her father refused to grant her a license.


First Crimes Arc

Rio fell from the sky attacking the three thugs that were ganging up on Shuto Katsuragi. She tells the thug that he can't pick on the weak on her watch. She performs the Frankensteiner to take him down. Another thug recognizes and introduces her. She thanks him for the introduction but thought the thugs were ganging up on Shuto. An angry Rio cracks her knuckles and proceeds to beat the thugs to a pulp for harassing Shuto.  Rio returns Shuto's shoe, which he accidentally kicked at one of the thugs. She says that she bet Shuto threw his shoe at them so he could teach those ashtrays a lesson, and calls him gutsy. Before Shuto could say anything back she stops, because this device she has says that something bad happened at the bus stop.
Rio meeting Ratman

Rio meeting an angry Ratman

After getting home and being informed that her father won't be home till tomorrow, she set her sights on training all night with Billy. However during their training Big Mama interrupted them and dragged her out, voicing how her father wishes for her to stop her dream of being a hero. So after training Rio relaxed in a bath with a drink, until the alarm of an intruder broke into her house. She rushes out of the bath, only to be standing naked before the criminal. She confronts Ratman but, she is distracted by the Jackies trying on her clothes which let Ratman escape. Angry at this, she mercilessly beats up the Jackies before chasing Ratman. It isn't until she realizes that Ratman must be after the Databank, she rushes over just as Ratman shows his anger to Ankaiser which completely terrorizes her. Seeing him as something of a demon, she throws many different artifacts at him in hopes to get rid of him, which provided the distraction needed for a Jacky to release a smoke bomb and escape.
Rio's Nightmare
Because of this encounter she continues to have nightmares where Ratman comes after her

It isn't until later when Shuto was trying to get something to eat due to the side effects of his Append Gear, she offered him a sandwich and they ate at a bench. After Shuto gave her a drink as a thanks, the two got to talking. Rio reveals to him her desire to become a great hero despite her father's refusal to ever give her a license. Shuto however encourages her dream, and reveals his dream to also become a hero. She laughs to this, not at his dream but how they quickly they were able to relate to each other despite it being their second time meeting. It was then that her device revealed a Jacky was spotted in the city and they rushed off.

She gets there just as a Jacky runs by them. Just before anything can happen, a D-Rank hero fires his arm cannon attack at him. While they continue their chase, Rio watches as Shuto jumps straight into traffic to save a cat that went into the street to get a fish the Jacky dropped. Realizing he twisted his ankle, Rio carries him back to school. Despite Shuto being completely embarrassed about his predicament, Rio assures him that what he did just then made him more of a Hero than anyone else. While on patrol she picks up a theft report describing a "tall man in black" and heads to the location and suddenly ran into Ratman. Thinking he was the suspect she attacked him not knowing that Ratman already defeated the real suspect. She continued to attack but Ratman kept dodging until she got tiered. Ratman tried to ask her to calm down and listen to him explain himself but she doesn't and tried to hit him one more time. Ratman catches her wrist and begins to explain as his mouth opens. Rio then yells at him to let her go as well as calling him a pervert and to get away from her. This caught the attention of two civilians who ran to call the cops, Ratman then lets her go and she collapse.

Threat of S Arc

Days later, Rio saves Shuto who is being beaten by other students. Afterwards, Rio talks with Shuto and gives him some advise on how to get stronger. The next days, Rio takes Shuto out jogging and shows him a point she passes when she jogs.

Normal Life Arc

Days later, Rio is talking with Shuto about what happened with his sister and then gives him some advise.

Hero Awards Arc

Rio invites both Shuto and his best friend to the Hero Awards. At their request of an autograph she calls out to Randolman by his real name. After a fire breaks out and Shuto goes missing, Rio goes off in search of him. Van Guardner catches up to her and tries to convince her to evacuate but she argues that because she invited Shuto she is responsible and that she needs to do something to help. Van Guardner reluctantly concedes and tells her to be careful in search for her friend.

During her search she felt a tremor and complained about the smoke blocking her view. She then thought she saw Shuto only it turns out to be the Jackies carrying Prismman. Not knowing what was going on she asked the Jackies if they were the ones who started the fire but Ruby Red tells her that it was them (Prisimman) who did it from their infighting and it was Ratman who tried to stop them. Regretting their actions the said they did not deserve to be heroes. Just then an explosion occurred and Ruby Red pushed a Jacky to safety and fell and grabbed a ledge. The ledge gave way but Rio grabbed him before he fell. Ruby Red tells her that he is too heavy and she should let go or else she will fall too and it does not matter since he will lose his license. She then yelled at him that he does not know that and at least for now he is still a hero and not to be upset and that there were some people who dream of becoming heroes but can't. Sapphire Blue and Topaz Yellow then helped her pull Ruby Red up. She does eventually find Shuto but just after his fight with Ankaiser and Van Guardner. She later visits Shuto in the hospital. After Hero Awards Arc. Some time after she invited Shuto and Kanta to her house and showed them a room filled with files on the heroes. To thank her for saving him, Shuto buys her a Shadow Mask Magic Belt replica.


View from above

After the incident with the hotel fire, Rio contemplates her situation with wanting to be a hero, yet her father refuses to grant her a Hero's License. While in class she notices the Jacky Combatants and follows them, eventually encountering Ratman. After a short chase through the hallways and out on the roof, she was about to try and capture him, but receives a message about an accident in the city. Ratman graciously aids her in getting to the scene (She briefly sees Ratman as Shuto but shrugs it off as a delusion) and gives her a first look at how heroes view the city from above. Despite her fear of heights, this pumps up Rio's desire to become a hero.

Unchain Arc

After a major drug ring is shut down, Rio shows extreme distaste over how the Hero Association covered up the matter and blamed the resulting explosion on the criminals. She later follows Teramishi and Takaki to their secret lab and was captured by Shiki. The Hero Killers are then dispatched to distract the Heroes from looking for her. However, when Ratman defeats Unchain and the lab is self-destructed, Rio is saved by Shuto when Shiki uses his psychic powers to levitate him up to her. Rio later forgives Shiki for his involvement.

Post-Unchain Arc

Rio meets up with F-Rank Hero Yavais during a shopping trip in Shibuya. Though initially she thinks of him as weak and a blowhard, his willingness to help like a real hero does impress her. The two later get into a fight with a street gang, though with the appearance of Ratman, the hoods are quickly defeated with Yavais bringing down the gang leader.

Later, Rio heads to the beach to he Taichi and his sister Anzu at the restuarant. After they finish with the service, Rio plays volleyball with the others against Bison Burger. When Ankaiser and Van Guardner stops the match, She asks then why they are their and listens as Van Guardner explains.

This experience boosts Rio's desire to become a hero even further, as well as make her more comfortable around Ratman. With Rio's personal trainer Billy leaving for the United States for his wife's surgery, she finally gets her chance to get a Hero's License from her father as Billy pleads with him, stating the she has trained and earned the right for the opportunity. Rio's father decides to give his daughter the chance by sparring with her, on the condition that she defeat him. During the match, he reveals that he was almost chosen to be Shiningman and that he's actually an expert in several martial arts. Despite her best efforts, Rio loses to her father, but he decides that she has earned the right, with her promising not to die before he does.

Hero Booster Arc

Rio's Hero Debut

Rio's Hero Debut

Rio makes her debut as a Hero, using an armored catgirl theme and some extra weapons designed by Andou Hironobu. Her Rank is unknown, but given her physical skills, she's at least a C-Rank. She shows off her skills by defeating an empowered low-ranking hero who had gone berserk after receiving the Hero Booster. During her first outing as a Hero. she seems to gain some fans due to the catgirl theme, (especially from Kanta Matsui), though she feels humiliated over the issue of having to announce her Hero Name.

She and the rest of the Hero Association were left in a state of confusion when the berserk heroes were suddenly stopped and rendered unconscious, (due to the actions of Jackal).


Finally inside the forbidden room.

Rio gets another surprise when Ratman and the Jacky Combatants suddenly break into her house again. She immediately goes into her Superhero Form in order to capture them, but is shocked when Ratman applauds her new position as a hero. She is even further shocked when Shuto reveals himself to be Ratman. However, after explaining his reasons for coming to her home, she agrees help him investigate her father's secret room and the mystery of Shiningman. Both become shocked as they learn of the incident in which Shuto was supposedly saved by Shiningman and the events which led to the death of Rio's mother.


Rio is a skilled hand to hand fighter. She can do eight sets of pad-hitting right after doing pair exercises while showing no signs of slowing down. According to Billy, the military already wishes to recruit her, despite her age. She first demonstrates this when she easily beat up three older guys without breaking a sweat.


  • Extremely Aggressive Fighting Style: Rio shows no mercy to criminals or bad guys and mercilessly beats them up, as seen when she cracked her knuckles and beat up a thug who was scared of her. Rio is a proficient boxer and practices multiple sets of pad-hitting, including jabs and straights. She is a wrestling fanatic and knows how to use the Frankensteiner. It can be implied that she knows other moves as well. Rio is ridiculously powerful for a girl her age. However, she is still young and inexperienced, and can leap into situations without assessing them first, which can lead to her being careless or getting blindsided.
  • Superhuman Strength: Rio has shown multiple feats of abnormal strength.  She is capable of breaking solid rock with her bare fists and is able to lift weights that were shown to be too heavy for other characters to lift.  She is capable of lifting 1,000 pounds with ease.


  • Hero Tracker:Rio uses this device to keep up to date with all the latest crimes and their locations, so that she can help out.
  • Rio's Hero Tracker
  • Rio's Jet pack
  • Rio Speed Across Town
  • Catgirl Claws Attack Mode
  • Calling Rio
  • Frankensteiner
  • Jet Pack:Rio's method of transport makes use of a short-range jet pack in order to get to various areas of the city quickly. Despite her fear of heights, this becomes her primary mode of transportation.
  • Catgirl Claws Attack Mode : Rio's gauntlets have retractable steel claws that aid her during close-quarters combat. Though she doesn't really like the cat-theme, she is able to use them to considerable advantage as they increase her range and ability to dish out damage.
  • Cat's Bell Choker : The Cat's Bell on the choker that she wears on her neck is actually a two-way communicator in which her tech support and battle adviser Andou Hironobu is able to transmit information to her.


  • Rio de Carnival : Rio unleashes a barrage of attacks, ending with an uppercut. This may be considered as her Killer Move or Finishing Technique.
  • Rio de Carnival
  • Rio the Beat Carnival
  • Rio The Beat Carnival : Combining her Rio de Carnival technique with her metal claws gives Rio a devastating new Killer Move. To initiate the move, she knocks her opponent off balance then goes into a flurry of slashes and strikes.


Shuto Katsuragi

They have been friends since Rio saved him from a group of thugs and appears to have grown a romantic interest in him when he saved a kitten from getting hit by a car, despite not having any powers. They eat lunch together. Rio invited Shuto and Kanta Matsui to the party for the heroes. Later on, she saves him from some bullies and gave him a pep talk on never giving up, (which incidentally made him decide to continue as Ratman). She eventually learns that Shuto is Ratman though harbors no ill will towards him at this point and helps him with his search of her house.



Ratman & Rio fighting side-by-side

She was greatly terrified of him, constantly having nightmares of when he first showed his teeth towards Ankaiser, However she became dedicated to one day bring him down herself. She later seems to have mixed feelings for him after hearing how Ratman stopped Ruby Red during their fight, admitting she can't figure him out. Although, after he helped her reach the scene of an incident to help the victims of a car crash she seems to see him in a different light. In later chapters she seems to show hostility towards him, but can now fight along side him without fear or believing he is somehow involved in the criminal activity, showing she now trusts him to a degree. Her encounter with Ratman in Chapter 35 shows that she's willing to accept help from him in a fight.

After the Hero Booster Arc, she actually helps Shuto/Ratman break into the secret room at her mansion to learn the truth about Shiningman and the S Gene, showing she now trusts him.

Andou Hironobu

Rio's father hired him to design and build her weapons and equipment, as well as be her technical and tactical support.Since his new company is now her sponsor, Rio has the embarrassing duty to announce herself as Catgirl Rio, representative of Andou Electronics.


Rio considers him as a glory-hungry idiot, though she does respect him for wanting to help others like a real hero.


  • She initially has Acrophobia (Fear of Heights), though she seems to get over this fear as she begins flying about with a jet pack after receiving a Hero's License.
  • Though she does represent Andou Electronics, she's most likely directly sponsored by the Hero Association, due to her father being the president.
  • Rio becomes the fourth hero to find out about Shuto's identity as Ratman.