3rd P.O.V
In the Principal's Office, there are Jon, Principal Nezu, and the Big Three of U.A., Mirio Togata, Hado Nejire, and Tamaki Amajiki and you were wondering why they were there. Cause Principal Nezu or Magistratus Nezu will explain that aliens exist, the Plumbers, and that Jon had an alien device called an Ultimatrix turning him into all kinds of aliens with different abilities and it's not a Quirk that makes three of them stunned and speechless that aliens exist within their planet and their new substitute teacher is a Galatic Hero who saves multiple times within their universe from total annihilation or destruction.
Mirio: "U-Unbelievable..."
Tamaki: "......"
Nejire: "So you're saying that aliens exist and you guys were an Intergalactic Law Enforce in space! *Look at Jon* And the new substitute teacher is a Galatic Hero who saves multiple times with the power of this watch that can transform him into one of those called aliens?"
Jon: "Well you got all of that right."
Then Nejire quickly placed her hands on Jon's shoulder and began shaking him furiously.
Nejire: "I want to see it! I want to see it! I want you to transform into one of your aliens!? Pretty please~"
Jon: "O-Okay, but s-top s-shaking me!"
She stops shaking Jon making him dizzy.
Nejire: "Hehehe~ Sorry~ It just I can't believe that aliens exist and that you and the Principal were part of the police force from outer space."
Jon: "Don't worry you'll get used to it and I'll show you guys one of my aliens."
Mirio: "Amazing! Who knew that aliens exist and that they already lived among us, am I right, Tamaki?!"
Tamaki: "R-Right?! But why do you guys tell us this?"
Nezu: "That's simple I want one of you three will become a part-time partner of Jon during one of his mission of investigating or reporting any kind of alien activity here in Mustafa or Undertown."
Mirio and Tamaki: "EH?!"
Nejire: "*Raise her hand* Oh! Pick me! Pick me! I would love to see where alien lives and who they look like!"
Tamaki: "But Nejire how about your Internship with Ryukyu?"
Nezu: "Don't worry I got permission for all of your three Internships that you guys will have a partnership mission with one of our Heroes meaning Jon *Look at Jon* And yes I already told them about you as well and aliens' existence."
Jon: "*Sigh* I know that you are the Magistratus here in this Plumbers HQ, but just inform Grampa Max about this first."
Nezu: "I'll be careful. *Look at the Big Three* If you don't want to join that's fine."
Mirio: "I'll join so that I can save millions like Jon-Sensei."
Tamaki: "I-I'll join in as well."
Nejire: "Me too! Me too! I'll join as well!"
Nezu: "Excellent then I-"
But before he could finish his sentence Jon and Nezu's Plumber's badge started ringing meaning that one of the teachers was in danger.
Nezu: "It's the emergency Plumbers alarm!"
The Omni badge shows that a map of the U.S.J area in the U.S.J shows two were in critical damage.
Jon: "It's Aizawa and Thirteen! Nezu, I will head there and deal since I am the fastest."
Nezu: "Okay and we'll be there as well for backup."
Jon: "Now you three will see me transform into one of my aliens. *He raises his hand* IT'S HERO TIME!"
Jon activates the Ultimatrix and rotates it until he sees the one he needed, then he presses the faceplate, and a green light flashes covering the Principal's Office while everyone is covering their eyes until the green light faded and they see one of Jon's aliens.
Then He suddenly runs fast leaving everyone in the room stunned by how fast this alien is also the papers that Nezu arranged were scattered throughout the office and he sighed.
Meanwhile
At the U.S.J the low-rate villains and the Leader of the League of Villains named Shigaraki and its creation called the Nomu to infiltrate the U.S.J by using one of his men named Kurogiri to transport them here and their objection is to kill All Might.
Aizawa and Thirteen were busy dealing with villains in the front entrance while half of the students of Class 1-A were separated cause of Kurogiri's gate Quirk.
After a few minutes, the other students that disappeared were trying to fight their way back to the Entrance Area.
Midoriya, Tsu, and Mineta were hiding in the water at the Shipwreck Zone as they watch Aizawa fight against the Villains after they survive from the Villains.
Todoroki, Bakugo, and Kirishima had no problems against the Villains around them and they are on their way back to the Entrance Area because Bakugo was absolutely annoyed by the warp gate guy makes him want to kill that guy.
Jirou, Yoayorozu, and Kaminari are also heading to the Entrance area, while the remaining students still fighting.
Jirou: "Look! There's Aizawa-Sensei! HIs still fighting those villains!"
Kaminari: "Should we help him?"
Yaoyorozu: "No! We need to regroup with the others. We need to inform them that we're safe asap."
They both nodded in agreement.
Thirteen is fighting against Kurogiri at the Entrance Area while protecting the students.
Kurogiri: "Black Hole which sucks up everything and turns it all to dust. That is an astounding Quirk you have, Thirteen. However, you are a Hero for rescuing people from disaster. As expected, your experience is less than the normal Hero."
Kurogiri made a portal behind her and start to rip her apart.
Thirteen: "H-He got me..."
Class 1-A: "SENSEI!!!"
The students of Class 1-A were frozen as they watch Thirteen get attacked by her own Quirk and fall onto the floor. Aizawa heard the student's voices which makes him worried about them.
Aizawa: "The kids!"
He looked in the direction where the voice came from.
Shigaraki: "Oi oi...You should keep your eye on your opponent you know~"
When Aizawa turns his head back the Nomu is standing in front of him and attacked him off guard.
Shigaraki: "I'll tell you, Eraserhead. This thing he's an anti-symbol of peace the bioengineered the Nomu."
The Nomu roars throughout U.S.J. Midoriya, Tsu, and Mineta watched in horror as the Nomu kept crushing Aizawa's face to the ground.
Midoriya: "Aizawa...Sensei..."
Yaoyorozu, Jirou, and Kaminari stop their run in front of the stairs as they saw Aizawa getting beaten up by the Nomu which makes them petrified.
Kaminari: "That's joke...Right?"
Yaoyorozu: "Aizawa-Sensei..."
Ashido: "What the heck is that..."
Kurogiri: "Looks like the anti-symbol of peace is going wild, hahaha!!!"
Sato: "Anti..."
Uraraka: "Symbol of peace."
The villains who were knocked out by Aizawa began to rise again because of the roar that the Nomu made.
Kaminari: "You got to be kidding me!?"
Shigaraki: "That's right my fellow Villains! Go kill them all!"
Suddenly the main door exploded sending a cloud of smoke around the platform. All of them were shocked as they looked at the door, but couldn't see anything because of the smoke.
Then a blue blur dashes towards Kurogiri hitting him in the stomach and sending him back towards Shigaraki's side which surprises him.
Kurogiri: "What the hell hit me?!"
Shigaraki: "Huh?!"
He scratches his neck while looking at Kurogiri lying down near the fountain.
???: "So you're the Villains who hurt my students and the teachers and by the way, this is my first time meeting them on my first day as a Substitute teacher."
They see a blue and dark furry that had an Omni symbol on its chest slowly walk out from the smoke.
Uraraka: "Substitute teacher *Realized who he is* It can't be..."
Fasttrack: "It's my first day as a Substitute teacher and you guys were trouble so, of course, I'll rescue you guys! By the way, call me Fasttrack in this form."
Class 1-A: "Jon-Sensei!"
End Chapter