Kazuhiro ended up on the other side of Tokyo. Kamui had to drive to the city where he was taken to. On their way back, the group drove passed Hosu. This was where the Hero Killer was operating so he must be close. Kamui noticed Kazuhiro gazing out to Hosu as he drove down the highway.

"Everything alright, Kimura?" Kamui asked.

"Yeah, it's just that… I had a friend whose brother was attacked by Stain," Kazuhiro said.

"Attacked?" Kamui took a second to recollect his memory. "You must be referring to Ingenium, the only hero who survived an encounter with the Hero Killer"

"Yeah, and last time I saw him, he had this… cold look on his face. I'm just worried," Kazuhiro said.

"Did you reach out to him?"

"I did, but that was a few days ago and he didn't even read it," Kazuhiro said. "A part of me thinks he's in this city.'

"Must be serious," Kamui said.

BOOM!

Suddenly, a loud explosion was heard in the distance. Kamui and Kazuhiro peeked over the side and saw a large fire. Kazuhiro turned to Kamui and asked, "Are we going to assist them?"

"Of course, we don't back down in the face of any disaster," Kamui nodded as he exited the highway. Kazuhiro felt a vibration in his pocket and pulled out his phone. It was just a location from Izuku on his location.

"What is this?" Kazuhiro thought. "Midoriya wouldn't just send a random message without a reason. Something must've happened."

Kazuhiro put away his phone and turned to Kamui, "This is probably bad timing but I need to check up on a friend in this area."

"You can do it after the disaster, the civilians in direct danger are our top priority," Kamui said.

"I get it but… he just sent an ominous text with just his location. I don't know if he's in danger or not."

"I see," Kamui said, taking a second to think. "Alright, I'll let you go check on your friend. If it's nothing then report back to me, however, if he's truly in danger then I expect you to let the Pros deal with it."

"Understood," Kazuhiro said.

Once they parked the car, they split up. Kazuhiro looked a the address, 4-2-10 Ekou Street. It looked like the exact location was in an alley nearby. As he sprinted down the street, Kazuhiro wondered what situation Izuku found himself in. Then the pieces started to come together. It was Stain, it had to be. This was Hosu; the city where he was last spotted.

Kazuhiro then wondered why Izuku of all people was calling for help the way he did. Was there no Pro Hero chaperoning him? Was he killed? Will Kazuhiro even make it in time? Should he call for help? Kazuhiro shook his head, not allowing the rapid thinking to get to him. Izuku was in danger. No Pro Hero was available to help him out since there was a disaster going on right now. This meant Kazuhiro was going to need to stand up.

When Kazuhiro turned the corner into the alley, he was shaking at the sight in front of him. Izuku and another Pro Hero were on the ground, conscious but seemingly incapacitated while a man with a sword held was approaching Iida.

"So that's Stain…" Kazuhiro thought. The Hero Killer a black combat suit with several small blades sheathed throughout his body. He wore a red scarf and a tattered cloth over his eyes to act as a mask. Stain walked up to Iida and readied his blade.

"Dammit!" Kazuhiro shouted as he summoned the Decadriver and a Rider Card. Stain turned as Kazuhiro inserted the card into his belt and pushed it together, wasting no time to help transform.

[KamenRide: Decade!]

"Tch, another one, Stain groaned. He looked at Decade, observing his appearance. "I recognize you. You're the one from the Sports Festival."

Decade summoned the Ride Booker, remaining silent as he mentally prepared himself for a fight. He summoned a card and inserted it into his belt.

[AttackRide: Blast!]

Decade fired a wall of bullets at Stain. The Hero Killer jumped back, leaping over the bullets. He landed a further distance from the three incapacitated heroes. Decade ran in front of them and transformed the Decadriver into a sword. He stood his ground, telling the Hero Killer that he would have to go through him first.

"Kimura! You can't let him lick your blood! It will paralyze you!" Izuku shouted.

"Good to know. This means his Quirk is complete-" Decade was interrupted by a knife striking his cheek.

Stain threw the knife, sparks flew as it scratched the surface of his helmet. Stain swiftly appeared in front of him, swinging a knife in a reverse grip at him. Decade blocked the attack with his sword. However, Stain leaned in before kicking away from Decade. He caught his sword in his hand.

"How annoying," Stain groaned, realizing that Decade's suit was cut-proof. He sheathed his knife. "This doesn't change anything. I know your Quirk is that suit, meaning there must be a limit for how long you can be in that suit. The second you're out of it, I'll kill all four of you."

"The consequences of being famous on TV," Kazuhiro thought as he readied his sword.

Without another second wasted, Stain charged at Decade with a scary tenacity. He used his katana to attack Decade. He initially tested Decade, seeing his strength and finding any exploits in his fighting style. Decade remained defensive against Stain. The Hero Killer fought with a tenacity even scarier than the villains he fought or the Kamen Riders he encountered.

Stain quickly used his left arm to swiftly unsheath a knife and strike Decade in the chest in one motion. Stain then struck Decade in the arm with the katana before slashing both of his blades and an X at Decade's chest. Sparks flew with each hit, which intrigued and annoyed Stain.

"Without this armor, this kid would've been dead," Stain thought as thrustted the katana at Decade's chest, sending him fly back. Decade summoned a card but Stain quickly struck his hand by throwing a knife. Decade then re-materialized the Ride Booker in his hand and opened fire at Stain, forcing him to be on the defensive.

"Kimura…" Iida groaned. "His fight is with me! I'm the one who inherited Ingenium's name! It should be me!"

Decade gasped quietly at Iida's plead. He never saw the class rep sound so desperate. There was a certain darkness to his tone. It didn't sit right with the Kamen Rider. Decade said, "If you truly inherited your brother's name, then act like it."

Decade quickly summoned an AttackRide card since Stain was occupied with blocking and dodging his bullets.

[AttackRide: Blast!]

Decade fired another rain of bullets at Stain to keep him away from the group. The Hero Killer quickly leaped onto the wall and used it to bounce further up. He threw two knives at Decade's head. The impact knocked him to the ground

"You're a good kid, unlike him!" Stain shouted as he dove straight onto the incapacitated Pro Hero.

"Dammit!" Decade shouted as he sat up. Izuku quickly leaped into the air and caught Stain by the back of his shirt. Decade gasped as he realized that Izuku finally mastered his Quirk since his limbs weren't flailing and there was a certain glow to his body.

The green-haired teen then dragged him against the wall and shouted, "Somehow I'm able to move!"

"So his Quirk has a time limit," Decade said.

"No, there's no time limit. I was the first one to get paralyzed and I still can't move," the Pro Hero groaned. Stain elbowed Izuku, knocking him to the ground. The Hero Killer landed on his feet but before Stain could do anything, Decade fired at him once again, forcing him back. Izuku quickly ran towards Decade's side.

"I have three theories on the powers of his Quirk: One, it's either weaker when more people are in its effects, two, the limit is based on how much blood he can ingest, or three, it's based on blood type," Izuku spoke out loud.

"Always the quick thinker," Decade commented. Stain remained distant, waiting for the two students to make a move. Stain knew about the results of the Sports Festival and how its rising star could use multiple forms.

"I was hoping we could get these two out of here, but he's fast," Izuku said as Decade nodded.

"Even with Kabuto, I could only go as far as up to ten paces before I'm back to normal. He'll quickly catch up to us and I'll be unable to do anything," Decade said. "Even if I use a finisher or try to attack, who knows if he'll go down?"

"It's two against one and you have the advantage of not being able to have any blood exposed," Izuku said.

"Two against one? No offense Izuku but you're exposed as a newborn baby," Decade said as spun around and inserted a Rider Card, doing it in an attempt to avoid getting his arm hit by Stain.

[KamenRide: Build!]

A rectangular mechanism formed around Decade as two pipes with red and blue liquid flow and form armor components on the model kit-esque part holder.

[Are you ready!]

The two components smash into each other, transforming Decade into Kamen Rider Build.

[The Steel Moonsault! RabbitTank!]

Kamen Rider Build's base form and other sub-forms consisted of two sides based on a specific motif. One side is based on biotic (living) objects, the other is based on abiotic (non-living) objects. The biotic side consisted of the armor's right arm, the right side of the chest, and the lower half of helmet. The abiotic side is the left side of the chest, left arm, and the right leg. There is an asymmetrical design on the chest and helmet. The divide on the chestpiece was slanted, with a stipe of the biotic side on the left. The helmet was designed with the abiotic taking up the upper and right side of the headwear with the biotic is represented on the right side and jaw of the helmet.

In this case, the rabbit is the biotic half while the tank is the abiotic side, which is colored red and blue respectively. Build's left lens was a tank with the cannon acting as an antenna. The right lens was a rabbit with its ear acting as the antenna. The leg of the rabbit half had a spring on the ankle while the foot of the tank half had treads. On the slanted divided was a tag sticking shaped like a rabbit ear and a tank cannon

"I'll deal with Stain alone. Build is equipped with multiple tricks up his sleeve, so I should be able to hold out," the Kamen Rider said. "And Iida? I know you're going through a lot but… you have a name to uphold, right? Try to be the hero your brother would be."

Build approached Stain, leaving the Hero Killer baffled. "Going against me alone? You think you could defeat me and take the glory for yourself?"

"I'm not in it for glory, I'm in it to stop a madman," Build said as he raised his fists.

Izuku could only watch on the sideline, knowing that Stain would prioritize him if he fought since he's vulnerable to the Hero Killer's quirk. If he tried to run or call, it would also make him a target. His best bet was to wait for Iida and the Pro Hero to be free from Stain's control.

Stain quickly swung his sword at Build but he summoned the Drill Crusher, a drill-like sword, and Build's primary weapon. Their weapons clashed and locked. Build took advantage of the opening and swiftly pressed his foot on his stomach and let the tank treads scrape against his stomach.

The Hero Killer winced as he jumped back. Build summoned a FormRide card and inserted it into his belt while the Hero Killer was off him.

[FormRide: RoseCopter!]

The same mechanism that transformed build into his RabbitTank form materialized. It quickly slammed the halves of armor onto him, transforming Build into a new form.

[The Passionate Fan! RoseCopter]

The biotic side was colored vermillion and represented roses. Blackthorns half of the chest and arm. The lens was a rose with a thorn as the antenna. There was also a small rose at the top of the divide of the chest piece. The abiotic side was turquoise and represented a helicopter. The lens was shaped like a helicopter with the tail as the antaena. The shoulder pad was shaped like the front of a helicopter. This form was equipped with the Batrotor Blade, a double-sided sword on his back.

Stain landed right as the transformation wrapped up. He quickly threw two knives at Build to throw him off guard. The Kamen Rider was quick enough to materialize the Batrotor Blade onto hand and blocked the two thrown knives last second. That was a small distraction as Stain was already closing the distance between the two of them. Build blocked an attack last second but Stain pulled out a second blade and jabbed it at Build's gut.

The Kamen Rider staggered back as the Hero Killer raised his sword and swung it down. Build raised the Batarotor Blade and blocked the attack. With his right arm, Build shot three thorny, black vines. They swiftly wrapped around his body and the Kamen Rider slammed him against a wall. He didn't let the Hero Killer react and slammed him against the parralel wall. Stain swiftly sliced through the vine as Build inserted the Decadriver into his belt.

[FormRide: NinNinComic!]

The transformation mechanism surrounded Build as it slammed a new armor set onto his body.

[The Shinobi Entertainer! NinNinComic]

The biotic side wasn't necessarily an animal but rather an occupation. It had a ninja motif and its armor pieces were purple. The arms were black and grey with a chainmail pattern. Build also sported a purple scarf. The lens was a shuriken with one of its sides extended. The abiotic side had a comic book motif. The chest had four comic panels of various ninja-like actions. The shoulder pad was shaped like a book opening. The lens was a book with an ink pen writing in it.

Build materialized the 4Koma Ninpoutou, a sword with four comic panels printed along it. The Kamen Rider pressed the trigger on the sword.

[Duplication!]

Several clones of Build surrounded Stain before him. The Hero unsheathed a knife. This fight was growing more irritating by the second. The Kamen Rider was an amateur but his resilience to stand after taking such deadly blows impressed him. It's almost like he had a shred of respect. However, to him, Kazuhiro represented the next generation of heroes in school. Killing him would set a fine example to make everyone else in those hero schools stay in line.

At the same time, several duplicates of Build rushed at Stain. The Hero Killer shifted his eyes as he quickly observed the oncoming ninja clones. They had predictable attacks and he easily diced through them, each clone puffing into smoke as Stain defended himself from multiple angles. Build managed to come close to attacking Stain from the side but the attack was blocked.

[Fire Skill!]

Stain glanced to his side to see an ignited Build leaping at him. The Hero Killer quickly threw a knife and struck Build in the head. The Build in front of him disappeared and Stain grinned.

"Found ya!" Stain shouted as he charged in at Build.

Izuku couldn't stand aside and into the fight. He threw a kick, which forced Stain back. Build didn't question or hound on Izuku for stepping in. It was just in Izuku's nature to step in when someone needed help. It was something he respected in his classmates.

Iida watched as Build fought Stain. Tears swelled as a mix of regret and anger raged in his heart. He realized he hadn't changed much since the entrance exam. Seeing Izuku finally master his Quirk is proof of that. Kazuhiro's last words to him began to resonate with him. Iida needs to be a hero that his brother would look up to, just like how he used to when he was an active hero. Just then, Iida began to feel movement in his fingers.

A small opening allowed Build to use another FormRide Card.

[FormRide: FireHedgehog!]

The transformation mechanism surrounded Build as it slammed a new armor set onto his body.

[The Rescue Pincushion! FireHedgohog!]

The biotic side was white and represented a hedgehog. Build wore a spike-covered shoulder piece equipped with a spiked glove weapon in the shape of a ball. The lens was shaped like a hedgehog with spikes acting as an antenna. The abiotic side is scarlet and represents a fire engine. His shoulder piece is shaped like the front of a fire truck along with a ladder as the armor's tag on the chest. His arm is equipped with the Multi Deluge Gun, a weapon mounted on his arm, and is designed after an aerial ladder with a hose. which can shoot water or extend.

Stain didn't wait a second and immediately went in for the attack. Build extended the Multi Deluge Gun to swing it like a polearm. Stain jumped over before running slashing his back Izuku tried to attack Stain but the Hero Killer dodged the attack and sliced his ankle. Izuku fell to the ground with a cut that made it hard for him to stand.

"You kids give me a lot more trouble than most Pros but this ends now!" Stain shouted as he rushed towards Izuku and he got up.

"Reciprio…" Iida grunted as he got up, the engines in his leg overworking itself to its max. Izuku raised his arms as realized the danger in front of him. "Burst!"

In an instant, Iida kicked through Stain's sword, shattering it. When he landed, Iida used the remaining juice in his Quirk to kick away Stain.

"Iida!" Izuku crired out in relief.

"About damn time!" Build exclaimed.

"Kimura… Midoriya… I apologize as this doesn't have to do with you. That's why I swear to you that you won't lose any more blood," Iida said as he bowed apologetically.

"Tch, someone's true nature doesn't change so easily," Stain said. He taunted Iida while giving a lecture. "You're a fake who prioritized his selfish desires. Cancer in this society is warped by "heroes". Someone needs to correct the system."

"Don't listen to him, Iida. He's just a villain with a twisted version of justice," Izuku said.

"No, he's right. I have no right to call myself a hero. But I won't let him break me," Iida said as he clenched his fist, blood dripping down his hand. "If I break, then Ingenium's dead."

"You're then really hopeless…" Stain said.

Build leaped at Stain, throwing a bunch with the spiky glove on his right. Stain dodged the but was sprayed by the Deluge Gun. Build summoned the Drill Crusher in its gun form. The drill was attached to the handle from the pointed end. The Kamen Rider opened fire, forcing Stain to jump up. Build focused on shooting Stain, forcing the Hero Killer to remain mobile. Izu

"Kimura! Can you cool off my legs?" Iida asked. Before Kimura could answer, Stain threw a knife from the air.

"You're in my way!" Stain shouted. Iida pushed Kazuhiro out of the way, taking the knife on his arm.

"Iida!" Izuku cried out once more. He tried to move but the wound on his leg prevented him from moving further. Izuku winced in pain and said, "I can still… move."

Iida turned to Build and said, "Just do it!"

Build aimed the Deluge Gun at Iida's leg and sprayed water to cool it off. Stain descended quickly as the Kamen Rider was momentarily distracted. Once Build saw a small puff of smoke shoot out of the engine's exhaust, he aimed the Deluge Gun at Stain. He extended the nozzle, pushing Stain back up into the air.

"Got it!" Build shouted. Iida quickly pulled the knife out of his arm with his teeth. He looked up to see that Stain was near the top of the building. He began to run down with murderous intent in his eyes.

"Thank you…' Iida said as he crouched down. "Reciprio…"

Izuku's body began to glow as green lightning sparked across his body. He muttered, "One for all…"

"Extend!/Full Cowling!" Iida and Izuku shouted.

Iida's engines began to work overtime after they had cooled off. Flames were shot out of the exhaust pipes as Iida jumped into th air and ran up the wall. As for Izuku, he leaped at an angle to make sure he met Stain in the air. The Hero Killer was too focused on Iida to notice that Izuku was flying straight at him.

"Go get him!" Build shouted.

Iida fired the engines on his leg while Izuku tapped into his Quirk and pulled back his fist. Iida kicked Stain in the stomach while Izuku punched him across the face. For a second, Build was convinced that Iida and Izuku managed to incapacitate Stain. That was immediately proven not to be the case as he unsheathed a hidden blade and sliced Iida on the shoulder. Iida used the engines to launch his leg into another devastating kick.

Meanwhile below, Build drew a FormRide card. Everyone was falling from a tall position and needed to make sure they at least made it to the ground safely. He inserted the card into the Decadriver.

[FormRide: OctopusLight!]

The transformation mechanism surrounded Build as it slammed a new armor set onto his body.

[The Lightning Technician! OctopusLight!]

The biotic side was magenta and represented an Octopus. It had a shoulder pad shaped like an octopus head with several tentacles acting as a shoulder cape. The lens was shaped like an octopus. The abiotic side was light yellow and had a lightbulb motif. Build had a lightbulb on his left shoulder. The lens for the abiotic side was a lightbulb with three streaks of electricity.

Build quickly used the shoulder cape from the octopus half to catch Izuku and Iida. He let Stain fall to the ground. Stain slowly got up on his two feet.

"This guy just can't stay down…" Build complained as he insert one final card.

[Final AttackRide: Bu-Bu-Bu-Build!]

Build aimed the octopus shoulder pad at Stain, firing a concentration of jet-black ink at him. It formed an orb around Stain, obscuring his vision.

[Vortex Finish!]

The Kamen Rider wrapped the orb of ink with the tentacles from his shoulder pad. He pulled Stain in and punched the orb. The amount of energy created an explosion that would surely knock out Stain.

"Thanks for the save, Kimura…" Izuku said as he got up. Build transformed back to Decade, as per usual after using a Final AttackRide card.

"No problem," Decade said. "Let's just get this guy restrained."

"We should probably remove all his weapons."

"Good point," Decade nodded. Iida could only stare at the unconscious Stain.

It took a while to remove the weapons from Stain's body. The Hero Killer was equipped with a variety of knives that ranged from switchblades to butterfly knives. Shortly after disarming Stain, Decade used some rope near a trash collection site. The Pro Hero that was in Stain's crosshairs, Native, helped Izuku up, carrying him on his back.

"Native, you can move, right?" Izuku asked.

"Of course I can," the Pro Hero said. "Let me help you, it's the least I can do."

"Thank you."

"Heh, I should be the one saying that."

As Decade finished tying up Stain, Iida stepped forward. He said, "Kimura, let me be the one to drag him."

"Look, you're arm is pretty messed up. Let me do it, alright?" Decade pointed out. Iida didn't protect since his friend had a point. While Native carried Izuku, Decade draggedStain with the rope while Iida followed him.

"I'm going to have to apologize, I'm a Pro but I was useless back there," Native said.

"Don't be. I don't think anyone could've fought against Stain in a one-on-one fight," Izuku said.

"Yeah, it took the three of us to defeat him, and even then we had a hard time," Decade said.

When the group exited the alley, they ran into Todoroki along with a short, old Pro Hero.

"Why are you here?!" the old man shouted.

"Gran Torino?!" Izuku cried out. In an instant, Gran Torino used his Quirk to close the gap between him and Izuku, kicking him in the face.

"Didn't I tell you to stay on the train where it's safe?!" the old hero snapped. "At the very least, you're safe."

"So I guess you got the text?" Decade asked.

Todoroki nodded and said, "It was unusual for Izuku to send a random text message, so I read it as a plea for help. I would've checked on you sooner but your reply immediately at least alleviated my worries. Still, I felt like I needed to check on you once things settled down."

"What exactly happened?" Decade asked.

"Nomus."

"Wait, isn't that the thing that attacked UA?"

"Well, that's what they're called."

"I was engaging in a fight with one of them until Endeavor showed up along with your friend. After we dealt with that Nomu, Todoroki immediately started to run to this address. Endeavor asked me to look after his kid while he dealt with the rest of the Nomus and promised reinforcements," Gran Torino explained.

"So this is where he told us to go," a Pro Hero said.

The group turned to see a group of five Pro Heroes approaching them

"We got a backup request from Endeavor," a hero explained.

"They're badly hurt! Call an ambulance!" another hero shouted.

A female hero noticed Stain and pointed it out. "Hey, that's the Hero Killer!"

"Huh? Call the police too!"

As the heroes call both an ambulance and the police, Iida approaches Kazuhiro, outside of his Rider form, and Izuku.

"Hey, kid, you're hurt. Maybe you should…" the Pro Hero paused as his words didn't go to Iida's head.

"Both of you were wounded because of…" Iida said as he bowed. "I am sorry… I was blind, and lost sight of everything…"

"I'm sorry too, I should've reached out to you better," Izuku said. Iida sniffled as he wiped his tears with a limp arm.

"Get down!" Gran Torino shouted as a winged Nomu swooped down out of nowhere. He grabbed Izuku before flying out of the scene.

"What the hell?!" Kazuhiro shouted.

As if he suddenly jolted into consciousness, Stain jumped up and leaned onto a Pro hero, licking blood off her face. This paralyzed the Nomu flying away.

"Both this sham-filled society and the criminals who wield their powers in the name of petty mischief…!" Stain said as ran towards the Nomu. He stabbed the Nomu several times in the head to make sure it's dead. "are targets of my purge…!"

Stain pulled the knife out of the Nomu's skull. He said, "For the sake of a better society."

Everyone was stunned by the Hero Killer's actions. They suddenly snapped back to reality as they heard a familiar voice barking orders.

"Why are you all bunched up together?! One of the villains was heading this way!" Endeavor shouted as he exited an alley across the street. "Huh, you're already finished?" The Flame Hero noticed Stain. "Is that…"

Stain stepped off Izuku, who he landed on top of by complete accident. He turned and said, "Endeavor..." Once Endeavor realized who it was, he immediately built up an attack.

"Hero Killer!" Endeavor shouted.

Gran Torino realized that Izuku would get hurt by the blast. He raised his arm to stop the Flame Hero from hurting his intern.

"Todoroki, wait!"

"You fake.." Stain said as he slowly walked towards the group of heroes. "If I don't fix it… if someone isn't stained with blood… If I don't reclaim my hero status…" Stain stomped on the floor hard once. "Come, just try me, you fakes! The only one allowed to kill me is All Might, a true hero!"

Stain remained still, his eyes whitening. A Pro Hero asked, "D-D-Did he pass out?"

Stain's cold-blooded declaration seemed to shake a lot of heroes present. Kazuhiro was also disturbed by it, but hearing all of this just disgusted him even more. The twisted, self-righteous crusade that Stain unleashed on Society killed a lot of Pro Heroes who didn't deserve death. This fight was a grim reminder that this world isn't perfect, even with hundreds of superheroes running around.

Author's Corner

First chapter of the year, let's go! I just want to thank everyone for being patient with me. The second half of season one is now on the roll, baby! Expect a chapter to come out bi-weekly since I'm still writing the remaining season and would rather just do it like this so that there are no more delays.

Anyways, let's talk about this chapter. For clarification, this does happen on the same day Decade meets Diend. I think I needed to point it out since I haven't posted a real chapter since November. As you may have noticed, Todoroki has been largely absent and Decade takes his place. In fact, I picked Build because of his half-and-half power system. This fight would've actually been a struggle for Stain if Todoroki was included alongside Kazuhiro.

That's all I have to say about the chapter. I do want to thank everyone for helping this story reach past 150 favorites and we're close to 150 followers. Knowing that this many people like my story or would want to follow it motivates the hell out of me.

Response corner

IzukuIchimonji (from chapter 17): We are far from any Hundred-League alliance. For now, the two are acting independently but we'll see how Hudnred is actually structured soon.

FlameFireZero X (from chapter 17): Diend will be hard to convince that he has a Quirk since his powers are tied to his equipment. Kazuhiro is intentionally the way he is because we want him to convince the inhabitants of MHA's world that he does have a Quirk.

KRZeronos (from chapter 1): I personally think that using a single Japanese in what's suppose to be translated dialogue is cringe. Again, these character Japanese speaking Japanese but we as the readers are suppose to understand what they're saying because the in-text dialogue is suppose to be translated. Also, I only use "Japanese" words when using names.