Mirea Mizushima
Kanji 水島尿素
Rōmaji Mizushima Mirea
Personal Characteristics
Gender Female
Side Against the Hero Association but not against the public
Family Gengo Mizushima (grandfather)
Tougo Mizushima (father-deceased)
Mrs. Mizushima(mother-deceased)
Crea Mizushima (sister)
Professional Characteristics
Power(s) None
Occupation High school student
Affiliation Jackal Organization
First Appearance
Manga Chapter 1

Mirea Mizushima (水島尿素, Mizushima Mirea) is a first year classmate of Shuto Katsuragi. She was the one who recommended that Shuto become Ratman. Her grandfather is Gengo Mizushima, and her sister is Crea Mizushima, the leader of the evil organization, Jackal.


She has long blond hair, which extends to the end of her shoulder blade. She has a very pale white complexion with. Since her mother was English, that makes her a mixed-blood child. She usually wears a school blazer with a mini skirt, and knee-level socks. She wears her uniform even in their hideout sometimes, with a apron during cooking or cleaning.


She has an icy exterior with a pretty face, which makes her unpopular with girls but also
Mirea Smiles

Her smile, which usually comes out around Shuto

unapproachable to the boys in her school (so much so that people are genuinely surprised to see a warm smile from her). This also due to the fact she could easily see most of the boys attention towards her was just a cheap attempt to hit on her, to which she would always coldly reject. She shows a warmer attitude towards Shuto Katsuragi, to whom she has a crush on. She cares about people close to her as she cooks and clean for them. She respects her sister, Crea Mizushima, and her actions.

Despite her icy exterior, she is actually quite warm and soft and reveals she has a weakness to cute things such as kittens and Mr. Boxer. Such as her desire to take care of the members of Jackal. This part of her personality is usually shown when around Shuto. She also shows a very shy side to herself, as she gets easily flustered when Shuto calls her by her first name, and she could not gain the courage to call Shuto by his first name as well.

However, while she has shown a softer side is also shown to be completely fearless when the situation calls for it. As when Shiki threw a rock at her she didn't even flinch before a Jacky caught it, and when Shuto completely lost himself to Ratman, she didn't hesitate to grab him and try to bring him back even at the cost of being injured. She also has a bit of a naughty side to her as well. When Shuto (who due to Gengo was reverted to the age of five both physically and mentally) proposed the idea of taking a bath with her, she can be later seen in the kitchen constantly thinking over the idea.



Young Mirea and her father Tongo

Not much is known about her history other than she was four-years-old when she and Crea first came to Japan. Mirea was five-years-old and living in the UK during the time of the S Project. She does not know of the truth of her parents' deaths. Several years later, she enrolled in the Shuto's school as a foreign exchange student.

When she first arrived at the school in search for a candidate for the Ratman project, even though she was unaware as to why or what her sister was planing. While there she was repeatedly flirted with by many guys. Seeing through to how shallow their attempts to come on to her she ignored them. Because of this she grew a reputation to have a cold personality and it wasn't long till most of her classmates despised her. Though she also didn't mind as she believed that being part of an evil organization that if someone got close to her they would just end up being hurt.

It wasn't until Shuto met with her the first time that he actually tried to get to know her and helped her out without even considering a reward for doing so. It wasn't long from these actions that Mirea developed feelings for him. It would be some time until her Mr. Boxer keychain that was given to her by her sister was stolen from by some of her female classmates out of spite. Despite being too embarrassed to tell Shuto of it being taken, he was able to realize it and find it for her. He then told her that he knows everyone has something they hold dear and doesn't believe in making fun of that, going on to tell Mirea that his dream is to one day be a hero despite his height.

It wasn't long after that Mirea decided that Shuto would be perfect for the Ratman Project.


First Crimes Arc

Mirea arrives in class, and asks Kanta Matsui and his friend to move because their were on her seat. Mirea and Shuto Katsuragi greet each other and she returns the book about heroes that Shuto let her borrow. Mirea says that she liked Chapter 4, The Significance of the Existence of Justice, Like the Relationship Between Light and Shadow. Shuto goes on to talk about the appeal of heroes and the notion of justice. While he was talking, she had a smile on her face.

After Shuto gets hurt from a fight he had during gym class, Mirea walks him to the nurses office. When he asks her why she's walking with him, she says because she is on the Student Health Committee. She asks what did Nagasawa say to him for them to fight. He says that he'll never tolerate someone talking about his height. Shuto talks about how one day he will become a hero. She tells him that he can do it, and that she believes in him. Shuto is embarrassed by this and and makes up an excuse to leave. Just after he left, she texted her sister, telling that their is a change in expectations, and to proceed with the plan today.

To trick Shuto into accepting the Append Gear, she set herself up to be the "innocent victim" that the Jackal Society were planning to drop into a vat of acid. It wasn't until Shuto, as Ratman, saved her did they all reveal their plan and how Mirea wasn't only just in on it, but her sister was the leader of the "evil" organization.

A day later, Mirea is at the base when the Jackies bring Shuto their.

Another day later, Mirea is walking to school with Shuto. While walking, Shuto reveals how good Mirea food is, which she offers to make his a bento. Later Mirea is shocked when she finds out that Shuto is having a lunch date with Rio.

The next day, Mirea meets with Shuto before he trains. She then tells Shuto that she make him a bento. They then talk about the others. Afterwards, she watches Shuto train within the virtual reality. After the training, she listens as the others tells Shuto about what is going to happen to him.

The next day, Mirea is cooking when he recieves a text about Shuto. She is then confused when she recieves another text about something else.

The next day, Mirea thanks Shuto for helping clean the base. She then prepare the food as the rest talk. While eating, Mirea drinks some liquid, which causes her to fall asleep.

Hero Awards Arc

Later, she asks Crea if Shuto is in the building that the hero awards are in. She then listens, when Crea explains that abilities of Ratman. After the incident, Mirea visits Shuto in the hospital. She then talks with Shuto until her sister arrives with the Jackies. After a while, Mirea winds up falling asleep while still at the hospital.

Days later, Mirea is talking with Shuto after he reveals that the Append Gear is acting up. When Shuto suggestion about making him taller, Mirea says that she prefers to the way that Shuto is now.

Threat of S Arc

After the Hero Awards incident, Mirea reveals to Crea and Shuto that someone has taken a picture of her with a Jacky. She then waits when Shuto goes to get the picture. Later when Shuto returns, she helps him when he collapses. When Shuto quits, She helps the Jackies make the cranes in order to get Shuto back. She then greets Shuto when he decides to return. 

Normal Life Arc

After the incident with the hero Kreios, Mirea is walking with Shuto and thinking about how she is glad that Shuto is happier. She then tries to thank Shuto for what he did, a Jacky runs by being chased. When Shuto goes to help Jacky, She is bumped put about the fact how she couldn't thank him.


Holding hands

A few days later, she heads out on a date with Shuto. While heading to the movies, she talkes with Shuto about how what kind of movies they like. When they get to the movies and begin watching it, she tries to grabs Shuto hand but is shocked when Shuto grabs her hand. After the movies, Mirea heads to Bison Burger with Shuto for lunch. She then begins eating, and says how she likes the food. After eating, She along with Shuto head to another place. While heading their she thinks about how she first met with Shuto and how she fell in love with him. They then arrive at the park where she and Shuto talked to each other a long time ago. When it starts to snow, she starts smiling and walks as the snow falls.

Unchain Arc

After discovering that Shuto has been led into a trap with Unchain, and learning of their parent's involvement with the original Shiningman project, Mirea decides to go to find Ratman before it's too late. She is confronted by Kreios, who uses his teleportation ability to take her to Teramishi's laboratory. Though she is initially unsuccessful in getting through the Berserk Ratman, Shuto eventually regains his humanity and the conspirators are arrested.

Post-Unchain Arc

After the Unchain incident, Mirea is at school. She then gets pissed when Shuto get happy while he talks with Anzu.

Days later, she heads to the zoo along with her sister and disguised Jackies. While at the zoo, she gets a chance to hold the baby Fennec Fox which result in it falling asleep in her arms. Later, she talks with her sister about how their parents brought them to the same zoo. After spending the day at the zoo, they head home which Mirea suggest that they hold hands.

Days later, Mirea heads to the beach with Shuto and the rest to his friends, to healp Pizza Fat with their beach restaurant. After the restaurant sells all their ingrediants, she then watches as the rest play volleyball against the employees of Bison Burger. She then notices Shuto's scar and asks about it. She then listens as Shuto tells her about it. After the volleyball game is stopped, she is walking with Shuto and talking about how fun it was and how they should come again sometime.

Rematch Arc


Shuto and Mirea share a private moment

Days later, Mirea helps Shuto when Crea is scolding Shuto for wanting to help Ankaiser. When a Jacky show then a report about Ankaiser, She watches as Ankaiser challenges Ratman to a rematch. She then listens as Shuto agrees to Ankaiser's rematch. After suddenly collapsing during gym class, Shuto is taken to the nurse's office where he and Mirea talk about the scar on his back and its connection to his encounter with Shiningman. The two share an embrace.

Hero Booster Arc

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Later on, during the time in which the heroes are running amok under the influence of the Hero Booster Program, Mirea is present when her sister begins experimenting on the berserk hero the Jackies had captured. Suffice it to say, the process was not very pleasant to watch.

After her sister and grandfather transmit the antidote to the Hero Booster Program and once again save the citizens from the rampage of the berserk heroes, Jackal Headquarters is visited by Shouichirou and Kreios. Despite the

Don't Shoot!

fact that Crea has a hatred of Rio's father and wouldn't have hesitated to shoot him, Mirea intervenes and stops her sister from committing murder. She manages to convince Crea to hear him out and give him a chance to explain his involvement with their parents' deaths.


She is very capable in household chores. She cooks and cleans ups for all the Jackal members.


Shuto Katsuragi

She was the one who recommended Shuto to become Ratman and makes his lunches for him. She has a crush on Shuto and when something happens to Shuto, she stops whatever she is doing. When she hears that Shuto is on a date with Rio, she drops her food. When Shuto was succumbing to Ratman's animal instincts, she drops her drink. It is later revealed that she is in love with Shuto, as she openly admitted to Shiki that Shuto was the most important person in the world to her.

Despite this, she also fully trusts that Shuto is capable of handling the situation despite the outlook. It is currently unknown where this strong belief in him comes from. Also while trying to get his attention, Mirea always tries to make food that Shuto would like to eat.


She truly loves her sister and wishes to help anyway she can, despite knowing that would make her technically be working for an evil organization. Mirea even stops Crea from shooting Rio's father when he came to confront them at Jackal HQ.


  • She seems to love school uniform a lot, as she wears her uniform even out of school.
  • She stated she likes her sister because she let her go to school.
  • She has a running gag where her excuse of being with Shuto is because she is a member of the Health Committee at their school. Even when she visited him in the hospital.
  • Mirea has a weakness for extremely cute things, especially the Mr. Boxers character.
  • Despite being a member of Jackal, she is not involved in any of the day-to-day operations. Technically she could even just been seen as a maid, as all she takes care of is cooking and cleaning for the members.