Moments earlier…

"Nomu, finish him," the cerulean teen commanded the hulking, black beast to end Aizawa's life. The beast nodded and brought its arm up, but was stopped when it heard something hurling itself towards its master. In a split second, the Nomu leapt in front of the projectile to prevent it from hurting its master, which was above him.

The cerulean teen looked up and saw Nomu blocking something from killing him unexpectedly, and this got the teen to smirk. After the brief exchange, the Nomu landed on the ground, while the mysterious attacker landed a few feet away from them.

What the teen saw was a person wearing what seemed to be leather armor with a ragged cape. They wielded a blade as long as a pole on their right, and a short, curved dagger on their left. But the most eye-catching feature of the person was the pointy, steel helmet that obscured the person's face.

All in all, he looked dangerous. But not as dangerous as the Nomu.

"I don't know who you are," the teen said while grinning madly. "But you made a mistake trying to kill the backline before the frontline first. Nomu, kill him."

The Nomu roared and rushed towards the unknown figure, who made a gesture unique to them, by tilting their head down and pointing their sword towards their opponents, while crossing their left arm holding the dagger above their right arm.

In one second, the Nomu reached the unknown figure and punched them with great force, sending them back meters away, a good crunch sound was echoed, causing some of the villains to recoil.

"That's what you get," the cerulean teen boasted as he eyed the corpse of their unknown assailant. Suddenly, a portal emerged from beside him, and his protégé emerged.

"Shigaraki, we need to leave," the portal man said. If you could read minds and emotions, you will realize that the portal man was panicking.

"Why, Kurogiri? Isn't the final boss going to appear sooner or later?" the cerulean teen, revealed to be Shigaraki, asked while glaring at the portal man, also known Kurogiri. "Don't tell me we need to kill more mobs to summon the boss?"

"No, it's not that," Kurogiri replied while eyeing the corpse of a familiar assailant. "We have a third-party intruding."

"Oh? Then more toys for Nomu to break," Shigaraki cackled as he scanned the area, trying to find any unknown trespassers. Kurogiri tried to reason with the man-child, but until Nomu is gone, Shigaraki won't relent.

The Nomu sensed another assailant coming for it, so the Nomu got ready. When it saw the attacker, it was another one, but had the same costume. Shigaraki also saw this and raised an eyebrow.

"Hm? Are they heroes?" Shigaraki questioned, mostly to himself, while Kurogiri just stayed in defense for his master. The Nomu winded up its right hand, and struck the incoming assailant, blasting them to who knows where while snapping their neck in the process.

While the Nomu was distracted with the other attacker, the Nomu felt a piercing pain coming from its back. When it shifted its head backwards, it saw another one of them. The Nomu retaliated by elbowing them in the head, gripping them in its giant hands, and crushed it like an egg.

The headless corpse fell down, blood pooling at the ground.

Shigaraki just smiled at the masterpiece that was the Nomu. The Nomu was made to counter All Might, no other hero could match up to it.

And that was a mistake Shigaraki would forever etch in his mind.

The corpse of the earlier attacker suddenly reanimated itself launched themselves towards the Nomu, brandishing their greatsword. Going on full offense, the attacker dodged a punch coming straight at them, and sliced at the Nomu.

"What the hell!? They have a healer on their team!?" Shigaraki screamed in irritation and frustration. "That's not fair! But it's okay, Nomu's still here… Yeah… Everything is still good…"

The Nomu grunted in pain for a moment, before launching a kick towards the overextended attacker, launching them into the air, then followed up with a haymaker, destroying their torso. And then, another one attacked the Nomu. It was the one who was sent flying to somewhere with a snapped neck.

With a grunt, the attacker effortlessly sliced of the limb of the Nomu. It recoiled in pain for a moment, giving the attacker an opening to continue its onslaught. Using the dagger, they stabbed the Nomu's eye and used their greatsword to stab through the huge body of the Nomu.

Then the headless corpse rose, a new head forming, then quickly swung, amputating the legs of the Nomu. It released a pained cry from the overwhelming sense of pain overload through its system.

Shigaraki, who saw this couldn't help but cry in frustration. "WHAT THE HELL! THAT'S CHEATING! CHEATERS! YOU EVEN USE BUGS! HACKERS!"

Shigaraki noticed one of them hurling towards him, and he held his hand out.

"DIE! YOU HACKERS!" Shigaraki caught the sword, but for some reason, the blade didn't decay. "What the fu-"

"Shigaraki!" Kurogiri made a portal behind Shigaraki and pushed him in, teleporting him to safety, but was a bit too late. On the spot where Shigaraki once stood, another assailant with the same form as the others appeared, along with a bloodied arm on the ground. They then rushed towards Kurogiri, who teleported himself to safety, back to where eyes couldn't see in this hell of a dome, and where they teleported, a pained scream emanated from Shigaraki who was clutching his stump of an arm.

But for the surrounding villains, hell just came.

"F-FUCK! KILL THEM!" a mutant-quirk villain screamed while charging towards one of them. He was rewarded with a quick stab towards his stomach and a gouged eye. His friends also followed suit, only to find their limbs separating from the bodies, courtesy of another attacker.

The villains panicked, and tried to run, but was stopped because when they looked on over, their faces paled in horror.

In front of them, about a dozen similar costumed attackers blocked their vision, all wielding the same weapons. But some of them had red glowing eyes and they were attacking the others in the same costume.

This confused some of the villains, but thought that they were on their side. Their morale shot up and helped the red-eyed attackers kill the other normal ones.

Another huge mistake.

Once a normal one was killed off, the red-eyed attacker then turned on the villains and hacked them to pieces. Screams, shrieks, cries, and groans echoed around the main plaza. All of this was visible towards the heroes-in-training above the stairs…

Where half of them were injured with grievous wounds, and the other half were not that injured and trying their best to stabilize their classmates.

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"Tsuyu, listen to me," Izuku told in a low tone towards the shaken frog girl. Of course, she would be shaken, the violence displayed in front of them could be nothing short of horrendous. Dismembered body parts, pained screams, dying groans, this type of situation happening in front of your very eyes could be nothing less then traumatic. "I want you to take Mineta, and when I give you the signal, take Aizawa and run as fast as you can towards the others in the entrance."

Tsuyu nodded shakily while Mineta couldn't help but release a bit of bile, but he repressed it from going out of his mouth, for fear of making a sound to attract the… Villains slaughtering their kin.

"And when you get Aizawa, whatever you do, don't look back," Izuku stated as he fished out his Knight Artorias set. In an instant, Izuku leapt into the fray, ignoring the screams of pain coming from the thugs and common villains. "GO NOW TSUYU!"

Tsuyu grabbed Mineta by the waist and carried him while leaping through the bloodied battlefield full of screams and agony.

There was one Izuku saw who was crying while clutching her stump of an arm, then there was another one dragging his body on the floor, leaving a trail of blood.

'No doubt about it, I'll have to go all out,' Izuku steeled himself and brought out Artorias Greatsword. Thanks to Artorias' soul briefly inhabiting his body, Izuku was able to gleam from it some information on how Knight Artorias fought. And Izuku noticed something familiar about these knights slaughtering every villain, and sometimes, even their own red-eyed compatriots.

'They move like Artorias, but more aggressive,' Izuku thought as he jumped over a corpse of a woman clasping her wound on the side, eyes wide with tears. 'I need to stop this now!'

Izuku dodged an incoming strike from a knight and retaliated with one of his own, stabbing the knight through the chest. Quickly moving, Izuku swept past the corpses of villains and knights alike, never looking back since he knew, these knights revive after a set amount of time.

'The abyss has overtaken them… Just like Knight Artorias…' Izuku thought as he decapitated a red-eyed knight and continued on, ignoring the extremely large amount of blood pooling on the floor.

A few more seconds later, Izuku came face to face with a rampaging Nomu destroying every knight in its path. Using its punches, kicks, and sometimes, its beak to tear apart the bodies of the knights. Everytime a wound was done upon the beast, it retaliated 10-fold. As if that wasn't enough, it even regenerated.

Suddenly, Izuku felt a huge pressure coming over him. When he looked over to where the pressure was coming from, he saw another knight with the same armor and weapon, only, Izuku knew, this knight was the strongest out of all of them.

Their blade ignited, and in a swing, decapitated the Nomu. Without relenting in their attack, they shredded the body of the Nomu, while having the other knights help with killing this huge beast for good.

The black body of the Nomu was reduced to shreds and finally, it collapsed to the ground, never to get up again.

The knight then blocked an attack coming from behind it. A red-eyed knight glaring at the normal knight. Without hesitation, the knight stabbed their swords through the body of the red-eyed knight, who then collapsed to the ground unmoving.

Noticing Izuku, the knight then turned their gaze on his form. Without words, the knight made a gesture towards Izuku, head tilted down, right arm extended forwards, sword pointing towards Izuku, and their left arm crossing over their right.

It was here, Izuku knew, there was no escape to fighting.