Kouta is a small boy, comparable in height to Minoru. He wears a buttoned shirt, black shorts and black boots. Kouta has short black hair and wears a hat with horns on the front.
Kouta has a cynical and jaded view on Heroes. This stems from his parents' deaths as he felt that they chose their jobs over him and abandoned him, which resulted in his negative perspective on Heroism. Kouta's negative view on Heroes has also caused him to despise Quirks and the current society in general, believing that the "corny powers" are responsible for all the misery in the world. However, after Kouta was saved by Izuku from Muscular, Kouta's jaded view has somewhat changed as he thanked Izuku for saving him.
Kouta is shown to be disgusted with indecency as shown with Minoru Mineta's perverted behavior, telling him to learn human decency before aiming to be a Hero; he even pushed him to his fall after catching him attempting to peek on the girls and didn't care that Minoru would get hurt from the fall. However, Kouta himself is seen having a small nosebleed after accidentally getting a quick glance at the girls of Class 1-A at the hot springs.
Two years ago before the current story, Kouta's parents sacrificed themselves to save civilians from a villain. As a result, they died from a truly heroic death; Kouta's parents were praised and celebrated for their actions befitting true Heroes. However, Kouta became devastated from his parents' deaths because they meant everything to him. Feeling that his parents abandoned him and chose their jobs over him, Kouta started despising Heroes. Afterwards, Kouta joined The Pussycats, a Hero team of which Mandalay, his last known relative, is a part. From then onward, Kouta followed and obeyed Mandalay and Pixiebob's orders without question even though he despises Heroes; this is because he has no other relatives and without The Pussycats, he would have nothing.
Kouta appears alongside Mandalay and Pixiebob when they introduce themselves to Class 1-A. After Class 1-A begin traversing the Forest of Magic Beasts, Mandalay tells him that they are heading back. However, Kouta isn't enthusiastic.
Later that day at 5:20 PM after Class 1-A arrive at the facility, Izuku asks about the boy, Kouta and wonders if one of them is his mother. Mandalay explains to Izuku that Kouta is her nephew and asks him to say hello to Class 1-A. Izuku introduces himself to Kouta. Suddenly, Kouta punches Izuku in his crotch and begins walking away. Tenya goes to check on Izuku and admonishes Kouta for his actions. However, Kouta harshly replies that he doesn’t want to be with people who want to become corny Heroes and walks away.
During the evening when Minoru attempts to peek on the females of Class 1-A in the hot springs, Kouta appears and pushes Minoru down, telling Minoru to train in human decency before aiming to be a Hero; Minoru curses Kouta as he begins falling back down. The females of Class 1-A thank Kouta for stopping Minoru; Kouta accidentally looks at the Class 1-A females and falls into the males’ hot springs from shock. Izuku catches Kouta using One For All Full Cowl.
Izuku brings the unconscious Kouta to the facility's office who has passed out from the fear of falling. In the office, Mandalay thanks Izuku for being there to help him. Izuku notes that Kouta doesn't like the concept of Heroes and explains that he along with many others grew up in an environment where they wanted to become Heroes; Izuku is surprised that Kouta has a jaded view on Heroes. Pixiebob explains to Izuku about Kouta's history.
During Class 1-A's training session, Kouta silently watches Izuku train with Tiger. Later that day at 4:00 PM, watching Class 1-A make their own food from afar, Kouta notes that their training is a waste of time and leaves; Izuku sees Kouta while walking back to his class.
On a cliff, Kouta is sitting alone. Suddenly, Izuku approaches Kouta with a bowl of curry, surprising Kouta. Izuku offers the curry to Kouta after surmising that he didn’t have anything to eat. Kouta demands to know how Izuku managed to find his secret base, to which Izuku responds that he followed his footprints. Kouta harshly tells Izuku that he doesn’t want any of his food or company and demands that he leaves. Kouta finds Izuku's training along with everyone else's training to be pathetic because all they want is to brag about their "corny powers". Izuku notes that Kouta’s parents were the water-type Quirk users, the Water Horse; Kouta is infuriated that Izuku knows about his parents and surmises that Mandalay told him. However, Izuku tells Kouta that he knows their names after hearing about them. Izuku offers his condolences, but Kouta doesn't take heed of it. Kouta expresses his contempt for the current society of Heroes and Villains; he is angry that they use their Quirks for violence just to show off and blames Quirks for being responsible for many deaths. Izuku sees that Kouta does not only have hatred for Heroes, but for Quirks and society itself. Izuku remains silent and becomes sympathetic to Kouta's circumstances. Kouta demands that Izuku leave. However, Izuku tells Kouta a story about his "friend" who was born without a Quirk. Izuku explains that his friend desired to be a Hero, but that dream was impossible without a Quirk and he could not accept the reality for a long time, so he tried many different methods to awaken his Quirk. Izuku tells Kouta the moral of the story; if you reject reality harshly, the only person getting hurt is yourself. Enraged, Kouta orders Izuku to leave and starts threatening him. Izuku apologizes to Kouta for not being able to offer any useful advice and leaves the curry on the ground for him. Izuku walks away.
On the night of the Vanguard Action Squad's attaclk, Kouta is confronted by the masked villain. He is communicated by Mandalei who asks him to return to the facility and apologizes for being unable to help him. The masked villain comments on Kouta’s stylish hat and wonders if the boy will trade the hat for the mask he despises. However, Kouta begins running away as the villain takes off his mask. The villain uses his Quirk to jump in front of Kouta. Kouta sees the villain’s face and becomes shocked; Kouta remembers watching the news about the villain who murdered his parents, the Water Hose. The villain has a simple augmenting strength Quirk and his most defining feature is the deep scar across his left eye left by the Water Horse duo. Kouta realizes that the villain in front of him is none other than the villain who murdered his parents. The scared villain prepares to attack while Kouta cries and becomes immobilized from fear.Suddenly, Izuku appears and saves Kouta from the villain’s attack. Izuku analyses the situation; his phone is broken as a result of tumbling to the ground from saving Kouta and didn’t tell anyone about his location, thus he doesn’t have any way of communicating for backup. Izuku notes that his top priority is to protect Kouta from the villain since he is the only one standing in the villain’s way. With no other options available, Izuku decides to fight the villain to protect Kouta. Izuku tells Kouta to not worry because he will save him no matter what; Izuku activates One For All Full Cowl and prepares to fight the villain who murdered Kouta’s parents.
Izuku fights against Muscular, but is overpowered in offense and speed. Just as the villain is about to finish Izuku off. Kouta throws a rock at Muscular. Kouta asks Muscular if he tormented his parents just as he is tormenting Izuku. Muscular is surprised that the Water Horse duo had a child and considers their meeting to be fate. Kouta blames the villain for his evil actions. However, the villain criticizes Kouta for trying to put the fault on him while admitting that he does not hold any grudges for the loss of his eye. Muscular mocks the Water Horse Duo for thinking that they could stop him with their pathetic power and prepares to strike Kouta
Suddenly, Izuku jumps at Muscular using One For All Full Cowl, telling him that he is the one at fault. Izuku analyzes that the villain's speed surpasses his own and the only slight chance of victory is to close their speed gaps. Izuku punches the villain with his broken arm, trapping it between the villain's muscle fibers. The villain mocks Izuku for thinking that his plan to put them in a position where speed doesn’t matter will work since his inferior strength won't save him. However, Izuku tells the villain that his job as a Hero is to put his life on the line for the sake of others; with no other choice, Izuku decides to unleash his Quirk's full power: One For All 100%.
Izuku uses One For All 100% against the villain, which blasts the villain with great force into the cliffside and also partially destroys the cliff due to the great impact. Kouta is sent flying away, but Izuku manages to grab Kouta’s shirt with his mouth and drags him back onto the cliff. After apologizing, Izuku decides that they should quickly escape while the villain is incapacitated. However, the villain is revealed to have used his Muscle Augmentation to reduce the impact of Izuku’s One For All 100%, although Izuku’s attack did injure the villain. Muscular compliments Izuku while Izuku is shocked that his full power did nothing Under stress and unable to think of a plan, Izuku tries talking his way out of this fight by asking the villain about the League of Villains’ goal. Muscular doesn't care about Izuku's question and joined the League of Villains just to have fun. Muscular removes his artificial eye with another one to show that he is being serious.
Izuku orders Kouta to grab on to him; Izuku uses One For All Full Cowl to jump and run away from the villain. Izuku manages to avoid the villain’s first attack, but barely avoids the villain’s second strike which sends Izuku and Kouta tumbling to the cliff again. The heavily injured Izuku believes going to the facility is the best option but realizes that his speed won't be able to outrun Muscular. Izuku quickly forgets about the plan considering the grave circumstances he is in and decides that he has no choice but to defeat the villain. Izuku tells Kouta to run back to the facility as fast as he can the second he clashes with the villain. Kouta doubts Izuku’s strategy due to his attacks proving to be futile. Izuku uses 100% Detroit Smash against Muscular which keeps him at b; Izuku orders Kouta to escape while he still can but the villain considers Izuku’s struggle to be in vain. The villain begins overpowering Izuku’s attack and begins pushing him into the ground while demanding blood and death. Izuku is barely able to hold back the villain’s strength.
Izuku is shoved into the ground by the villain. Suddenly, Kouta blasts water at the villain, demanding that he stop. However, the villain says that he will kill Kouta after he is done with Izuku. Furious, Izuku refuses to let the villain kill Kouta and begins pushing back the villain, eventually pushing the villain off him. Izuku uses 1.000,000% Delaware Detroit Smash against the villain, a powerful smack with incredible force that smashes the villain into the cliff. The villain’s artificial eye pops out and the villain becomes incapacitated due to the great force of Izuku’s attack. Kouta is in disbelief that Izuku would go so far to protect him even though he doesn’t know anything about him, as he remembers what Mandalay told him; that one day he will understand why his parents sacrificed themselves to protect the lives of others when he goes through a similar situation. He will also understand that Heroes risk their lives to save people so that one day someone can call them “My Hero”. Kouta cries in disbelief while Izuku roars with triumph.Izuku notes that his job isn’t finished and must inform Shouta and the Pussycats about the enemy’s strength. Izuku tells Kouta that they can leave the unconscious Muscular where he is because he won’t be waking up any time soon. Izuku says to Kouta that the wildfires will be a detriment and tells Kouta that they need his Quirk. Izuku asks Kouta to use his Quirk to save them just as he saved Kouta. Izuku has Kouta jump onto his back and starts running back to the facility. Running in the forest, Izuku encounters Shouta and asks him to take care of Kouta. While going back to the facility, Kouta wonders if Izuku will be alright, crying that he didn’t get a chance to apologize. Shouta tells Kouta that Izuku will be alright and advises him to thank Izuku the next time he sees him. 
At the facility, Shouta asks Blood King to look after Kouta. The Vanguard Action Squad's attack ends after Katsuki is captured.
Two days later, the doctor at the hospital Izuku is currently in hands him a letter from Kouta. The letter thanks Izuku for saving him and hopes that Izuku gets well soon so that he can thank him in person.
Quirk and Abilities
Water Creation: Kouta has a water-based Quirk. It has yet to be confirmed or revealed in the storyline if he can create or just manipulate water.
- (To Izuku Midoriya) "You're all freaking nuts...calling yourselves "heroes" or "villains" and going around killing each other like idiots. Talking about your Quirks all the time...all just to show off. Idiots."