Brahamastra

Endeavor scanned his surroundings, taken aback by the sight of the young individual who had defeated his son in the UA tournament. However, at the present moment, that wasn't his top concern. "Be careful! It's regenerating," he warned.

Izuku and Mirko both turned their attention to the Giant Nomu as it fully regenerated back to its original form. The creature raised its fist and brought it down upon the trio. Of course, Izuku dodged easily, and Mirko swiftly moved to carry the wounded Endeavor out of harm's way.

"Master, this is a dire situation. This creature is capable of regenerating incredibly fast—alarmingly fast. My primary noble phantasm isn't suitable for a situation like this due to its wide area-of-effect damage. I have two other noble phantasms that can assist in this situation, but we only have about a minute left. So, be quick, Master, or else you're on your own," Karna urgently informed Izuku.

Studying his target, Izuku pondered for a moment before deciding to take action. Timing was a critical factor, and the enemy possessed a formidable regeneration ability that required constant, strong, consecutive damage to wear it down. However, the time limit on a new servant was a massive issue.

"Mirko, I need you to listen to me now. Clear every single person in the vicinity—hero or not. It doesn't matter how you do it, even if you have to forcefully remove them. Get them all at least 500 meters away!"

Getting annoyed at Izuku's request, Mirko retorted, "You think you can order me and pull me away from this fight? Are you out of your mind?"

"Mirko! Do this for me, and I'll go all out in our duel."

Although she wanted to say something, the idea of facing Izuku at his full strength was more tempting than facing the Giant Nomu.

"Okay, fine. I'll do it." Mirko immediately darted towards the nearest civilian groups, helping them escape the inevitable battle.

"Endeavor, I'm going to be dealing massive fire damage to that thing, but it may cause a lot of damage to the city and harm people. When I give you the signal, you must do whatever you can to limit the aftereffects of my attack," said Izuku.

"You think you can order—" before Endeavor could continue, Izuku interrupted.

"Shut up and do what I say. We don't have time for this. People's lives are at stake, and I can only maintain this form for less than a minute."

"Fine, I will do it," said Endeavor reluctantly.

"Alright, let's do this, you ugly bastard."

Izuku immediately darted towards the Giant Nomu, slicing its hands and then kicking it in the chest, forcing it to fall. While preparing for another attack, the Nomu unleashed its fire breath on Izuku.

"You idiot, I'm immune to this! Ugh!" Izuku exclaimed. But before he could finish his sentence, the monster punched him away. The fire was a mere distraction.

"Oh, I see how it is. I've got to admit, you got me on this one," Izuku thought, spitting some blood from his mouth. "Blood... most likely my blood, meaning Karna's power is waning. I should end this, now."

"It's time to finish you off."

With incredible speed, Izuku looked like a red laser, slashing both the legs and hands of the Nomu, shocking it. Without giving it a moment's rest, he immediately activated his attack.

"Endeavor, NOW! Don't let my attack spread!"

"{O' Brahma, cover the Earth! Brahmastra!}"

Izuku's right eye unleashed what resembled a beam shooting from his eye, targeting the last remaining uncut part of the giant Nomu and completely obliterating the Nomu from existence.

With his power dissipating, Izuku looked forward to see the monster eradicated and sighed in relief. "Thank God."

"Endeavor, how did things go on your end?" asked Izuku.

"I managed to contain some of it. Who was that summoning kid? I've never seen someone use flames as powerful as that," asked Endeavor, genuinely curious.

"Huh, well, that was the son of the Sun God, Karna. Don't even try to compare your flames with his. He's on another level."

Jumping from the sky, Mirko showed up and said, "All done? That attack has gotten me excited, kid. If you don't summon someone as powerful in our duel, I'll beat you to a pulp!"

...

Ida, Shoto, and Katsuki had tied up Stain, carrying him towards the nearest heroes for arrest.

"How did you know I was here, Bakugo-san?" asked Ida.

"I didn't, tsk I was told by Izuku to come to this city with my mentor. He said something about this being a chance to use my power for real, and I guess he wasn't wrong."

"So it was Midoriya-kun. I must thank him afterwards," said Ida.

"I didn't expect you to send me a message, Katsuki," said Shoto.

"Honestly, I didn't think I would ever do something like that. But Izuku said that I should learn to rely on others' help if I'm to have any chance of beating him."

"Does that mean you're relying on me?" asked Shoto.

"Hell yeah, I am. I've known Izuku since we were kids. I can assure you that if we all teamed up against him, we would lose in a heartbeat. I always try to defeat and act up against him, but deep down, I know alone, I stand no chance."

"Well, I'm not you. I will surpass him," Shoto replied.

"You think I'm giving up on that? Hell no. I'm saying that from now on, I'm going to use you, and you are going to use me. We both will surpass that guy!" exclaimed Katsuki.

"I should take lessons from Izuku in creating strong bonds. Just by insulting you two, he has managed to turn you into strong allies," humored Ida.

"SHUT UP!" x2

Arriving at some hero camp, the team surprised the heroes by presenting Stain in custody. Just like in the anime, another smaller bird-type Nomu was running away from Endeavor, who was finishing up the remaining Nomus, allowing Izuku to take a brief rest. This led to the same scenario of the Nomu kidnapping someone. However, this time, it wasn't Izuku but Bakugo, who was too exhausted from his fight with Stain to save himself. Stain leaped in to rescue him, and just like in the anime, when Endeavor arrived, Stain delivered the heart-rending speech that would inspire villains across Japan to rise up.

...

"Shame I didn't get to witness that speech. I was a big fan of it in the anime. Nevertheless, this is advantageous for me. Events will unfold as planned, and I shall seize this opportunity to eliminate certain villain groups before they can grow further."