It wasn't the first time the students had faced a giant robot, as they had encountered them as obstacles during the U.A. entrance exam and during the first game of the sports festival, but with their experience learned in that world, they knew that nothing was what it seemed, so they had to tread carefully.
Unfortunately, that wasn't the case for a certain explosive student, as he immediately launched himself towards the sentinel with his explosions.
"As if an ugly robot is going to scare me!" exclaimed Katsuki as he went zooming towards the robot's face. "Die!" shouted Katsuki hitting the robot's face with a blast, knocking it back a couple of steps, but it looked unharmed from the attack.
"Yes! Way to go, Katsuki!" exclaimed Eijiro cheering his partner on.
"Don't think it's over." said Pietro.
"Analyzing." began the sentinel turning his robotic gaze to the student. "Identification: unknown. Powers: generation of explosions through the palms of his hands. Danger level: high. Beginning adaptation process."
With a smirk of arrogance, Katsuki let out another blast to launch himself back towards the robot with the intention of hitting it again. However, in the middle of his trajectory, the sentinel pointed his hand at him, in which, a hole opened up and a small tube came out of it.
Before Katsuki knew it, the sentinel shot out a powerful jet of foam that hit Katsuki, knocking him to the ground and covering him in foam.
"What the hell was that?!" asked Katsuki as he spat out the foam from his mouth.
"It's a sentinel. It's programmed to analyze mutant powers and adapt to the circumstances." explained Wanda.
Shoto began to cover his right side with ice.
"Then let's see if they adapt to this." said Shoto before launching an icy wind that ended up freezing the robot completely, the same way it did in that race at the sports festival.
They started to think they had the win, but then...
"Analyzing." began the sentinel in its frozen state. "Identification: unknown. Powers: ice emission, similar to that of the mutant known as the Iceman. Danger level: high. Beginning adaptation process."
Suddenly, the sentinel began to emit a wave of heat that was melting the ice that held him prisoner, to the surprise and horror of the students and young mutants.
"H-he's breaking free!" said Kyoka.
"Looks like he's been upgraded since last time." said Bobby.
"It doesn't matter how upgraded it is. We need to take it down before things get worse." said Laura.
"Proceeding to mutant elimination." said the sentinel as multiple turrets and missile launchers came out of his shoulders, body, arms, and hands.
"Something like that?" asked Kurt fearfully.
"Scatter!" shouted Tenya just as the sentinel began firing missiles and energy beams.
Lorna held out her arms, trying to use her powers on it, but for some reason... nothing was happening, much to the young mutant's confusion.
"What? It doesn't work? What's it made of?" asked Lorna before the sentinel aimed at her and shot an energy beam, but before it could reach her, Pietro grabbed her and quickly pulled her away from the impact zone.
Pietro ran swiftly all over the place, dodging all the beams the sentinel shot at him. Using his computer brain, the sentinel calculated the speed and trajectory of the young mutant and upon completing those calculations, shot at a certain area, which happened to be where Pietro would step just seconds before.
The resulting explosion at the right moment was enough to bring down both mutant brothers. Without wasting any time, the sentinel shot several missiles towards them, but Wanda stepped in front of them and generated a shield that managed to protect them from the missiles.
One missile was headed directly towards Ochaco, who was paralyzed with fear, but before it hit her, Kitty managed to reach her and with her powers, they managed to get through the missile, but couldn't avoid the explosion that occurred when the missile hit right behind them, which ended up pushing them forward and falling to the ground.
Kyoka plugged her headphones into her wristbands and slammed them into the ground, sending a seismic wave that shook the ground until it cracked, but the sentinel could see the attack and activated the thrusters on its feet to rise high enough to dodge the attack, much to the student's surprise.
The sentinel began to swoop towards her to hit her, but in mid-flight, a missile hit it, causing it to stop. Kyoka turned her head to discover Momo with a bazooka on her shoulder.
The sentinel changed strategy by landing on the ground and launching its energy beams at the two students, who tried to dodge them, but the beams were too fast for them, and they ended up being hit and knocked down.
"Momo! Kyoka!" shouted Tenya wanting to go help his classmates, but he was busy focusing on dodging the sentinel's beams.
Unfortunately, no matter how fast he was, the beams shot out in an even faster sequence than he did. So, the sentinel shot a beam that managed to hit Tenya right where he was going to stop.
Rogue was scared of having to fight a sentinel, but she had to do something to avoid a catastrophe. Looking around, she found Katsuki dodging another shot from the sentinel. With an idea in her head, she ran to him.
"Sorry about this." said Rogue before taking off her glove and tapping Katsuki on the shoulder, making him groan in pain.
"What was that for?" asked Katsuki angry at what the young mutant did.
"We'll talk about this when we don't have to face a deadly robot!" said Rogue putting on her gloves and positioning herself to shoot off. "OH!"
Unfortunately, it was her first time using such a power and she ended up shooting uncontrollably into the air. However, in the short time she had known Katsuki, she could see how he was able to handle his power, so, thanks to that, she was able to regain her balance in mid-flight and shoot straight towards the sentinel.
When she got close enough, she extended her arms forward, managing to launch such a powerful blast that she forced the sentinel back a couple more steps.
Rogue smiled as she saw that she had landed a big hit on the robot, but that smile was wiped away when she saw the sentinel aiming at her, but before she was hit by the beams, Kurt teleported to her side and grabbed her before the two teleported away just before the beams hit them.
Both mutants reappeared back on the ground.
"Thank you." said Rogue to her blue savior.
"Anything for you, sister." said Kurt before he heard a noise and they turned to see the sentinel preparing to shoot again, but Kurt teleported them away from an incoming beam.
Mina slid to the side due to the acid secreted in her feet to dodge an incoming beam and then threw several jets of acid at the sentinel that managed to melt small parts of its body, but also got its attention.
"Analyzing." began the sentinel with its gaze on the rose-skinned student. "Identification: unknown. Powers: acid secretion. Danger level: high. Proceeding to elimination." said the sentinel pointing its weapons at her and preparing to shoot.
"Get away from her!" shouted Eijiro stiffening his body and charging towards the sentinel.
With a strong leap, Eijiro reached high enough to manage to hit him in the chest, close to what appeared to be his core. However, despite denting him, the robot seemed oblivious to the blow and struck the student, sending him flying into the wall.
Tsuyu jumped to the side to dodge a missile and shot the sentinel several balls of special liquid into the robot's eyes, believing that would blind it, but that proved wrong as the robot expelled water from the sides of its eyes and brushed the liquid off before aiming its weapons at her.
Before the beams hit her, an ice beam, courtesy of Bobby, struck the beams, managing to neutralize them, but the resulting explosion was strong enough to knock Tsuyu down, though Bobby managed to grab her before she fell to the ground.
"Take that!" shouted Denki throwing a powerful electric shock at the sentinel, but although he seemed to be suffering from the attack, he was able to move and direct his gaze to the student.
"Analyzing." began the sentinel despite the electrical attack he was suffering. "Identification: unknown. Powers: emission of electricity, similar to that of the mutant known as Storm. Danger level: medium. Beginning adaptation process."
Suddenly, a sort of antennae came out of his arm that attracted all the electricity from the attack, much to the student's surprise.
"It has a lightning rod?!" asked Denki in shock.
Before he could further process what was happening, the sentinel redirected the electricity from the lightning rod into his hands, from where he fired a powerful lightning bolt that struck the Quirk of Electricity user and knocked him down.
Laura let out a battle cry as she pulled out her claws at the same time as she ran towards the sentinel. With a leap, she grabbed onto the mutant's leg and with the help of her claws began to scale the massive robot until she reached the core, which she began to claw at with her claws.
While it only caused a few scratches, the sentinel could notice it and directed its hand towards her. By the time Laura realized it, it was too late, as the sentinel grabbed her hand, holding her prisoner and putting it in front of its face.
"Analyzing." the sentinel began, looking at the captive young mutant. "Identification: X-23, daughter of the mutant known as Wolverine. Danger level: High. Proceeding to disposal." said the sentinel before beginning to squeeze her hand, causing Laura to scream in pain.
"LET HER GO!" spun Izuku who had lunged towards the sentinel with the help of his Quirk and when close enough, he delivered a powerful kick to the robot which, not only caused it to release Laura, but caused it to stagger backwards, to the point where it almost lost its balance.
Before Laura hit the ground, Izuku grabbed her nuptial style and landed on the ground on her feet.
"Are you okay?" asked Izuku with concern.
"Ugh. I'm fine. Thanks for saving me." said Laura.
While the two were focused on each other, the sentinel steadied himself and focused his gaze on the green-haired boy.
"Analyzing." the sentinel began. "Identification: unknown. Powers: strength and speed greater than normal human. Possibility that it was restrained. Danger level: maximum. Proceeding to immediate elimination." said the sentinel, whose last words caught everyone's attention.
It was then that everyone watched as the sentinel's core began to spin like a washing machine and emit an almost blinding glow.
"Commencing self-destruct sequence in 30 seconds." said the sentinel, causing the students and young mutants still standing to stand in horror, thinking this was the end.
But shortly after the countdown began, a strange reddish aura covered him and lifted him into the air. Everyone turned their heads to discover Wanda with her hands outstretched and a look of rage on her face.
"Nobody messes with my family and friends!" exclaimed Wanda before she waved her hands a little, causing the robot to start squeezing like a tin can.
With little time left on the countdown, Wanda had managed to turn the sentinel into a metal ball and with her powers, threw it high into the air just as, a couple of seconds later, it exploded.
Although it was far away, the explosion was powerful enough for the wave to reach them in the form of a strong and brief gust of wind.
Finally, they had managed to defeat the sentinel, but several of them had fallen in the battle. Soon after, Professor X, Colossus, Forge and Mei appeared and were horrified by the scene in front of them.
They wasted no time in taking all the wounded to the infirmary where they would be treated for their injuries.
They were all in the academy's infirmary treating the injuries they received during the fight against the sentinel. While most of them had suffered minor injuries, others like Tenya, Momo, Kyoka, Denki, Tsuyu, Pietro and Lorna had suffered injuries that made them have to stay in bed in order to recover.
Izuku was relieved that all of them didn't suffer very serious injuries or worse. Although he was glad that they were all okay, he couldn't accept the fact that even though they had the numerical advantage, they couldn't do anything against the sentinel. Had it not been for Wanda and her powers, all of them and possibly, everyone in the academy, would have died.
"I'm so sorry, Professor. We couldn't do anything against that robot. Had we done anything else, we wouldn't be in this situation." said Izuku.
"Don't blame yourself, young man. It's not your fault that that sentinel showed up." said Professor X.
"But you were very lucky. Not many mutants can hold their own in a fight against a single sentinel." said Colossus.
"The worst part of all this is that it may not be the end." said Forge.
"What do you mean? Is another one coming?" asked Mina scared at the thought of fighting more of those robots.
"Knowing how they work. Yes." said Kitty.
"And he won't come alone. It's possible he'll come with two or three." said Kurt.
"I hope so! I want revenge on that damn scrap heap!" said Katsuki.
"Oh, come on. Don't you remember that one of them hit you really hard?" asked Rogue.
"Shut up, power-stealer! I still haven't forgotten what you did to me before!" said Katsuki angrily at Rogue, as that reminded him of how that Class 1-B student acted during the cavalry battle.
"I don't get it. What are those... sentinels? Why were they chasing us?" asked Shoto.
The three adults present looked at each other in a sort of mental debate for a few seconds until they came to a conclusion.
"Follow me. We'll explain everything to you in a more private area." said Professor Xavier.
"But what about them?" asked Ochaco referring to those who were resting.
"Don't worry. They will be in the best of hands here. They will recover in no time." said Professor Xavier with a reassuring smile.
With that reassuring the students, they, along with the young mutants followed the adults into a room where there was a table similar to the one they saw in the mansion of the second squad of Avengers.
"So, what exactly are these sentinels and where did they come from?" asked Izuku.
"You see, shortly after the existence of mutants in the world was discovered, some people in the government saw us as a threat to humanity. That's when Bolivar Trask appeared." began Professor X showing a holographic picture of a man. "He came to the government with a project that would help humanity fight against the mutant threat, Project Sentinel." continued Professor Xavier showing a hologram of several Sentinels.
"Project Sentinel?" asked Mei.
"It was a series of robots programmed to locate, capture or kill mutants." explained Professor Xavier.
"And it didn't matter if you were a woman, child or old man. If you were a mutant, they would find you and capture or kill you." said Forge.
The seven students were horrified to learn that a machine had been designed to kill people. It didn't even matter if it was an innocent civilian or a criminal. If he were a mutant, he would be targeted by these robots.
They couldn't help but imagine if such a thing were to happen in their world. That someone would build robots to eliminate anyone with Quirk. For Mei, that technology would come to be used in such a way made her sick and horrified her.
"What happened next?" asked Shoto.
"One day, we received a message from the future." said Professor Xavier.
"From the future? How is that possible?" asked Eijiro in surprise.
"That's not important now. The point is, that message told us about the terrible threat posed by the Sentinels." said Professor Xavier.
"What do you mean?" asked Ochaco.
"As we have already explained to you, the sentinels were programmed to wipe out mutants, but because more mutants are emerging every day, the sentinels had to make an adjustment in their calculations and came to a conclusion. To eliminate the problem, the source of everything had to be wiped out." said Forge.
"And what was the source of the mutants?" asked Izuku fearing the answer they were going to give him.
"The humans." replied Colossus, to the shock of the students.
"T-The humans?" asked Ochaco.
"Yes. The sentinels deduced that to wipe out the mutants, they had to wipe out the human race that created them. In the future, the war was won neither by humans nor mutants, but by machines." said Professor Xavier.
The students were shocked by this. A future where machines ruled the planet. Such a thing they had only seen in science fiction movies and such, but they hadn't expected the world they were in to have had anything like that.
"If that was a message from the future, what did you do to prevent it?" asked Shoto totally interested in the story.
"Because the sentinels were so powerful, we had to make a temporary alliance with Magneto and his kind." said Colossus.
"Man. You can realize how powerful an enemy is if you have to ally with other villains to defeat him." said Eijiro swallowing saliva at the memory that they were many against a single sentinel and almost died.
"The enemy of my enemy is my friend. We may have our differences, but we both wanted the same thing, the survival of mutants." said Professor Xavier.
"What happened to the project Sentinel?" asked Mei.
"It was a bit difficult, but we managed to convince the government by showing them the consequences of the project Sentinel. After that, the project was cancelled, and all the existing robots were destroyed." said Professor Xavier.
"All except one." said Izuku.
"Yes. Where did this one come from? I thought there weren't any of those left." said Bobby.
"What about Trask? What became of him after his project was cancelled?" asked Wanda having a little theory.
"He didn't take it very well. He went as far as to insult the president by calling him a traitor to humanity and the like. After that, his company went bankrupt and disappeared. He hasn't been heard from since." said Professor Xavier.
"Wait, are you suggesting he's creating sentinels again?" asked Kurt.
"Well, considering he hates mutants and was pissed when his project was cancelled, it makes sense that he would go to work on his own." said Kitty.
"And that's bad. If he continues to manufacture sentinels, he'll not only wipe out mutants, but he'll also wipe out humanity." said Forge.
"We can't allow that!" exclaimed Bobby.
"I know, but unfortunately, the X-Men are busy on their mission, and it would take quite some time for them to return." said Professor Xavier.
"Then we'll take care of it." said Laura with a serious look on her face.
"Laura, I understand your frustration, but this is too dangerous for you youngsters. You barely survived one." said Colossus.
"That doesn't matter. By the time, the X-Men arrive, that bastard will have created enough sentinels to wipe out an entire country. We must stop him as soon as possible!" said Laura.
"I agree with her." said Izuku to the surprise of his companions. "I know we had a hard time defeating just one of those robots, but that's more than enough reason to stop that man as soon as possible. If we don't, a lot of people will suffer, and I don't intend to stand here in the meantime."
"I never thought I'd say this, but I agree with Deku." said Katsuki before a feral grin formed on his face. "Besides, I want to make the bastard who built that damn robot pay." said Katsuki slamming his fist into his palm.
"I don't want to sound cowardly, but I think, with my Quirk, it would be best if I stayed here to make sure the others recover." said Mei.
"Relax, we understand." said Mina.
The three adults looked at each other before turning to them.
"Very well, you can go take care of business, but Colossus will go with you and in case things get complicated, you will return immediately. Understood?" asked Professor Xavier.
"Don't worry, professor. We won't take any risks." said Wanda.
"As good as the plan is, there is still one important point to keep in mind. Where is Trask supposed to be?" asked Rogue.
"I think I may have the solution." said Professor Xavier before heading elsewhere, with the rest following him.
After a couple of minutes of walking, they all came to a room that looked like the inside of a giant sphere, with a bridge leading to the center, where there was a machine that was connected to a helmet through several wires.
"Where are we?" asked Ochaco.
"Guys, welcome to Cerebro." said Forge introducing the place where they were.
"Cerebro?" asked Eijiro.
"It's a machine capable of amplifying the professor's power, allowing him to be able to detect any human or mutant on the planet." explained Colossus.
"Really? that's amazing! I had heard of a device that amplified Quirks in our world, but I never expected to see anything like it in this world! Let alone something as big as this!" exclaimed Mei excitedly.
"And this will help us find Bolivar?" asked Shoto.
"Let's hope so." said Professor Xavier as he put on his helmet. "But we lose nothing by trying."
Shortly after the helmet was put on, the entire room began to glow red and multiple silhouettes were shown everywhere moving. Some looked white while most looked blue.
Needless to say, the students were completely amazed at that.
"Those are... all the humans on the planet?" asked Izuku in amazement.
"Yes. The ones that are blue in color are all the mutants out there. Some of them haven't even awakened their powers and don't know they are." said Forge.
The students looked around and at every point they looked, seven out of ten people were mutants. Before they thought that world was similar to their own, but now they believed it was closer to resembling their own than they could have imagined.
All that was missing was for mutants to be accepted and for a hero licensing law or something like that to be passed.
"There. I've located him." said Professor Xavier as he removed his helmet, disconnecting himself from the device which went dead.
"Where is he?" asked Laura.
"In a hidden military base in a mountain range in western Asia." replied Professor Xavier.
"Good. I'll go prepare the other X-Jet for the trip. While I'm at it, I'll input the coordinates for easier travel." said Forge.
"Very well, young men. I hope you're ready because we're going straight into the lion's den." said Colossus.
With a nod from all, the steel mutant, the six students, except Mei, and the six young mutants left to prepare for the journey to where Bolivar was manufacturing the sentinels that, if not stopped, all the inhabitants of the planet would be doomed.