AN: So to address a small issue that was pointed out to me in the comments: I was not thinking of Tokyo in terms of being broken down into wards and cities. So Izuku and Emily are interning under Majestic in the Erad City, located at the edge of Tokyo. They were then proceeding to travel to Tachikawa City, which just so happens to pass through Hosu City. I'll be going back and revising the text to make that clearer.
Stain was perched on the rooftop, silently stalking his prey: the hero Native. Not only is he guilty of cultural appropriation, borrowing his look and style from an ancient American culture, but he was inconsistent in his ideals, often letting lesser crimes go overlooked in a search for high-profile cases. A true hero would help everyone, and not just chase glory.
This made him the perfect choice as Stain's final target in Hosu.
As the day stretched into evening, Stain finally made his move. He already knew the hero's patrol routes, and it didn't take long for him to find the hero, silently tailing him from the rooftops. When the opportunity came, he dropped into an alleyway and intentionally kicked a trash can, spilling its contents and causing a commotion. An amateur mistake, one that he would never make, but if he was right, the false hero wouldn't realize that.
"You! You're the hero killer!" Stain smiled with satisfaction as he heard the hero behind him.
Spinning around, Stain drew a sword. "And you are a false hero who is asking to be cleansed."
"No! I am the one who is going to take you down!"
Stain flashed a predatory grin, "See if you can catch me then."
Turning around, Stain began running. He didn't need to look to know the hero was following him - his steps were loud and messy. As he expected from such a hero, he thought he was the predator, when he was really the prey.
And Stain had already chosen the perfect place to show him how wrong he was.
Tenya was out for an evening patrol with Manual. Despite his less than noble reasons for choosing the Normal Hero for his internship, he had been pleasantly surprised by the hero's knowledge. He had assumed that because his ranking was in the upper 200s, he wouldn't have much to learn from the hero.
He was wrong. The hero had a solid head on his shoulders and was connected to his local community in a way that Tenya never saw with his older brother. Sure, Team Idaten was popular and loved by the community, but Manual was willing to stop and talk with people on the street, often calling shop owners by their first name as he asked how their day went.
It was a side of heroics that Tenya had never thought about before, simply due to his family's position. However, now that he was seeing it, he was thankful for the opportunity.
As their patrol wound down, an alarm went off on Manual's phone. Looking concerned, he held up his hand, telling Tenya to stop as he pulled out his phone. Whatever he was reading must have been bad, Tenya noted, when he saw Manual pale slightly at the news, before turning his phone screen towards his intern.
"Three monsters have just appeared in the shopping district, and the heroes on scene are having trouble containing them."
Tenya felt his stomach churn as he saw the image on the screen. "N-Nomu!"
"You've encountered these monsters before?" Manual asked in surprise.
Tenya adjusted his glasses and nodded. "Yes. During the USJ incident. The details were kept out of the news, but the villains had a Nomu among them. It took the combined efforts of several of my classmates to merely incapacitate one."
"And there's three of them," Manual had his thumb on his chin as he thought about the implications, "this is bad. I'm not sure how much help we can provide, but we need to join them." He looked at Tenya with determination on his face, before he turned around. "Follow me!"
Tenya watched as Manual started running down the street, but hesitated as he remembered the original reason he had signed onto this internship: Stain. According to the Hero Killer's pattern, tonight he would strike again.
Tenya put his hand on his chin as he thought. "Does this mean that Stain has thrown his lot in with this so-called League of Villains? Are they using the Nomu as cover to allow him to strike at his target without worry?"
He looked to the sky. "Tensei… what would you do in this situation?"
In the past month, thanks to Izuku, Tenya has found himself asking the question more often than he would care to admit. Sometimes the answers came easily, other times they were much harder to find.
However, in this case, the answer came immediately.
Looking at the retreating form of Manual, Tenya couldn't help but bow deeply. "I am sorry Manual, but I hope you can handle these Nomu without me. Another hero's life is in danger, and I must try saving them."
Remembering his research, Tenya knew that if the Hero Killer was working with the league, then he prefers to work in lonely alleyways away from the action. Turning in the direction opposite Manual, Tenya powered his thrusters and took off at full speed.
Away from the action, two figures stood on top of a lonely water tower, their presence overlooked by the heroes and media whose attention was focused on the rampaging Nomus.
"Perfect, perfect!" Tomura exclaimed as he watched the action through a pair of binoculars before he threw his head back and laughed. "See Hero Killer. This! This is how you send a message!"
As he looked through the binoculars again, Tomura watched as one of the Nomu proceeded to use a fire-breathing quirk to start a blazing fire in a storefront. "Yes, chaos, destruction, power. This is exactly the message we need to send. Join the league, and we will offer you a chance to burn society to the ground. And then! Will rebuild a new society from the ashes!"
"It appears the young Master is discovering his motivations, after all." The silent specter of Kurogiri finally spoke. "It seems that he was right, and given enough time and encouragement, the young Master will be a worthy successor after all."
"Did you say something?" Tomura tilted his head as he asked his companion.
"I was merely saying you seem to be enjoying yourself."
Tomura's manic smile grew. "Of course I am!" He raised his binoculars again and turned his attention back to the scene, where heroes had begun arriving in an attempt to contain the Nomu. "I can't help but think about what we can do when we have an actual party, and not just hirelings and Nomu to work with. And with this sort of advertising, surely we'll find some worthwhile party members!"
"Warning, due to an ongoing situation in Hosu, the train will be making an emergency stop. We are sorry for the inconvenience. Warning, due to an ongoing situation in Hosu…" The automated system began to drone as the train came to a halt.
Izuku looked towards Emily and Majestic. "Wait, what's going on in Hosu?"
Frowning, Majestic pulled up his phone and pulled up the hero network. "There's an active attack. Three creatures appeared suddenly in the shopping district and began rampaging. Currently, the heroes on the scene aren't enough to properly contain them."
There were several shouts from other passengers and people were pointing out the window. Izuku turned and saw a winged creature flying past. "Nomu?! Here?"
"It seems like you know more than a lot of the heroes in Hosu, then," Majestic said from beside him.
Izuku turned toward the hero. "That was the creature that attacked us at the USJ - although this one is different. The one at the USJ couldn't fly."
"I see," Majestic clapped his hands, "There is a general call for all heroes to assist. While I would have preferred a less exciting situation, heroes rarely get to choose their battles. The real test is how they handle the cards they have been dealt."
Izuku and Emily turned towards each other, and then back to Majestic, nodding. "We're ready!"
"Excellent. Follow me then!"
Majestic led the pair to the end of the car to the emergency exit and opened it. In the narrow gap between cars, he deployed a magic ring. Emily climbed on top of it before floating out into the open sky. Izuku was next, and finally Majestic generated a third ring for himself; the three now floating above Hosu ready to assist the heroes.
"The reports say there are two additional Nomu in that direction," Majestic pointed to a rising column of smoke in the distance, "but I believe thanks to myself and young Song, we should assist with the flying Nomu."
"What about me?" Izuku asked.
Majestic turned towards Izuku. "Your job is to watch our backs. We don't know if these creatures are the only things out here tonight, or the prelude to something else."
Without another word, Majestic took off in pursuit of the flying Nomu, while Izuku mulled over his words.
Something else out here.
Like a bolt of lightning, realization struck.
Stain!
"I'm sorry, I know what else is going to happen!" Izuku called out to Emily. "I have to go."
"What? No! You can't!"
Izuku shook his head, "You two are fine without me. Majestic was right. These Nomu aren't the only ones out there. The Hero Killer's also here."
"What? Are you seriously going after the freaking Hero Killer?!"
"Someone has to!" Izuku called back, "since everyone is focused on these Nomu, someone will die if I don't!"
"You'll die if you go after him!"
Izuku gave Emily a sheepish smile, "Sorry, but it's like Majestic said. We have to know where to lend our support. I'm no good up here, but on the streets below…"
Emily started to say something, but Izuku stopped listening, and instead angled his ring downward, shooting towards the buildings below. Once he reached the rooftops, he began skimming across the surface of the rooftops, looking for signs of the Hero Killer in the alleyways below.
It took longer than he would have liked, but Tenya finally found him - the Hero Killer.
Fortunately, he wasn't too late. He saw a wounded hero propped up against the wall, as Stain was raising a sword over his head. Pushing power into his engines, Tenya charged at the Hero Killer, leaping at the last moment to direct a thruster-powered axe kick to his arms, knocking him and his sword away from the hero.
"Who dares interrupt me?" An angry snarl came from Stain.
"I am Tenya Ida, successor to the Ingenium name."
"Kid, he's too dangerous! Run away while you can." Native yelled from his position on the ground.
Tenya spared only a second to look at the pro hero. "No, I cannot." He turned his attention back to the Hero Killer and held up a fist for emphasis. "For the honor of my brother, I will stop you! Your killing spree ends tonight!"
"I see, so you're just another false hero," Stain crouched and drew another sword. "I was only intending to kill one tonight, but if I can cut another off before they fully bloom, it will be worth it."
"F-false hero!?" Tenya was insulted by the insinuation.
Stain pointed his sword at Native. "If you were a true hero, your priority would be on protecting the victims in an attack. Instead, you are here to satisfy some feud. That's not particularly heroic, now is it?"
"That is where you're wrong." Tenya swept his arm for emphasis. "If I merely collected this hero and ran, then what? Either you would try to kill him at a later date, or you would simply choose another hero to stalk and kill. Am I wrong?"
Stain's eyes narrowed, telling Tenya everything he needed to know. He pounded his fist into his palm. "Therefore, the only true way to protect him is to stop you!" Tenya adjusted his glasses. "While you are correct that I am selfish in choosing to avenge my brother as well, both objectives have the same goal, and end in your defeat and capture."
A savage grin spread across Stain's face. "I see, so you do have the seed of a True Hero inside of you, even if falsehoods cloud it." He pointed his sword at Tenya. "Very well then, let's test your conviction, hero. Show me that you are worthy of being spared and that I give the seed inside of you time to grow."
Stain charged at Iida, who used his thrusters to dodge quickly. He was shocked at how fast the Hero Killer moved, and even with his enhanced speed, he was barely able to dodge the blow, having to rely on his shaped armor to properly deflect the swing.
"You're good kid. I'll give you that." Stain gave him a fierce grin, giving Tenya the chance he needed to confirm his suspicion.
He has a pair of elongated fangs, just like the older Midoriya. That means he has a blood-based activation condition for his quirk.
That would explain the sheer volume of blades the Hero Killer is carrying. While his armor could deflect the weapons at sufficient speeds, he had enough exposed areas, most notably his head, that the Hero Killer could easily exploit.
"If I was merely good, I wouldn't be worthy of the Ingenium name! I must be better, in honor of my brother!"
Not waiting for the Hero Killer to make the next move, Iida engaged his thrusters and charged. He saw the Hero Killer preparing a counterattack and dodged to the side at the last moment, before lifting his leg and activating his thrusters to deliver a spinning thruster kick to the Hero Killer's back, knocking him off balance.
The Hero Killer refused to let up, drawing and throwing a knife even as he tried to regain his balance. Tenya effortlessly dodged the first knife, only to see a second knife already on its way. Training kicked in, and he raised his arm at precisely the right moment, knocking the knife off course and sending it flying upward.
He is an amazing foe. It is a shame his ideology is so twisted.
With a flick of his wrist, Stain pulled the knives back to himself, further confirming Tenya's suspicion. With practiced skill, he caught the knives before throwing them a second time. Tenya responded by charging the Hero Killer, deftly sidestepping the knives at the last second before he slammed into his foe, carrying him into the wall of the alleyway.
Tenya felt a sharp pain as he was cut by another knife that Stain had managed to draw. Knowing he couldn't let the Hero Killer drink his blood, he grabbed Stain's wrist and twisted it, causing the knife to clatter to the ground. With a swift kick, he sent the blade flying. The moment of distraction was enough for the hero killer, who managed to twist himself free of the hero's grasp. Stain proceeded to grab Tenya and hurl him across the alleyway, where he collided with a dumpster with a loud clang.
As Tenya tried to quickly recover and stand he felt a sting across his cheek as one of Stain's daggers landed true. Eyes going wide, he saw the Hero Killer pull the dagger back into his hand. Not giving his opponent any time, his long tongue reached out, licking up the crimson substance and activating his quirk.
With a gasp, Tenya felt his motor nerves seize up completely, causing him to collapse onto the ground.
"W-what-!"
"I must applaud you, future hero." He saw the boots of the Hero Killer slowly approach him. "There aren't many who were able to identify Bloodcurdle so quickly, and recognize the threat of me drawing blood."
As Tenya was forced to watch helplessly, he saw the Hero Killer pull a wicked-looking dagger out, and hold the dagger over his arm. He slid it back and forth as if analyzing Tenya's costume before he plunged the blade into a gap between plates.
"Tonight you will live, but take this as a reminder of your transgression. Discard your false ideologies, and walk the path of All Might, the True Hero."
Tenya tried to suppress the scream but failed as he let out a pained howl as he felt the blade sink deeper into his arm. "You'll pay for this!" Tenya called out defiantly as Stain stood back up.
"One day, yes. One day All Might will come for me, and I will gladly pay for my sins in full. But you are not All Might, and he is not here. Therefore today is not that day." Stain walked over to retrieve his discarded sword. "Now then, to finish off this false hero and finish my mission."
Tenya was forced to watch helplessly as Stain slowly approached Native, sword ready for a killing blow, when suddenly, he saw a disk-like object slam into Stain at high speed, sending him flying into a wall.
"I'm not going to let you hurt anyone else!"
Tenya's eyes widened as he saw Izuku land in a crouch in front of him, body wrapped in the green aura of Full Cowling.
Elsewhere in Japan, at the Ryukyu agency, Himiko was standing in front of a projector alongside Nejire and their mentor. When the hero got the alert about Hosu through the Hero Network, she took the students to one of her meeting rooms to show them how an incident is handled in real-time.
"Those look creepy!" Nejire exclaimed as she saw the images of the Nomu coming in. The older girl shuddered at the image of their wide eyes and exposed brains.
"T-those are what attacked Izu and his friends back at the USJ," Himiko said, her knuckles white as she gripped the back of a chair. "Why are there more of them? Why now?"
Ryukyu frowned as she was reading the reports. "That points to a deeper conspiracy," Ryukyu added a note on her tablet, "I'll have to ask around and see who is taking the lead on this investigation. Probably Endeavor, since he is the highest ranked hero on scene." Ryukyu turned her attention back to the computers, and with a couple of mouse clicks the images on the projector changed to show Endeavor engaging what looked to be an oversized lizard-mutant.
Their discussion was interrupted by Himiko's phone going off, indicating that she just received a new message. Hoping it was her friends checking in, she grabbed her phone and opened up the message.
"GPS coordinates… from Izu." Himiko felt her heart sinking.
Nejire grabbed the phone and looked at them, before staring at the map the hero had pulled up. "These coordinates are in Hosu."
The screen then confirmed Himiko's fears as she saw a different image, one of Majestic and Emily engaging the flying Nomu in an attempt to keep it away from civilians on the streets below.
"What are they… doing in Hosu?" Himiko asked, as her head began to fill with worst-case scenarios.
AN: And the day started off so well, too!