Saitama soon had you, Ruby, Weiss, Blake, Yang, and Genos in his apartment. 

Saitama: Look, I don't need any students or disciples. Can you just g- 

Ruby: NO! We can't go without at least learning something from someone like you! 

(Y/N): You're so powerful! I mean, you took out that monster with just one slap! I mean, that kind of power ... it's... incredible! 

Genos: I agree completely. 

Saitama: How are you all healed up? 

Genos: Most of my body is mechanical, as long as I have the parts, then I'll be alright. 

Yang: Say, Saitama, what about your head? 

Saitama: Yeah, that's just skin. 

Everyone: HUH?! 

Genos: That is incredible. That would have to mean that you went bald at such a young age. 

(Y/N): Or maybe it's a birth defect. 

Weiss: Would that even exist? A baby just never growing any hair as they age? 

Blake: Well, we have seen pretty crazy diseases and oddities, so I don't think it's an impo- 

Saitama: SHUT UP! I'M JUST BALD! WHAT'S YOUR PROBLEM! 

Eveyrone: Wait, you want to know about us? 

Saitama: Yeah, no thanks, I'm good. 

One short introduction from you and the girls... 

Genos: It is a pleasure to make your acquaintances, my comrades in arms. 

Ruby: Oh there's no need to be so formal, Genos! 

(Y/N): What about you? 

Genos: Four years ago ... I was a normal human being until I was about 15. I lived a peaceful and relatively happy life together with my family in this dog-eat-dog world. But one day, a crazed cyborg went out of control and attacked our town. A runaway cyborg ... I suppose a failure in his body modification generated an irregularity in his brain. He was destroying everything, parks, school, buildings, even my house. He even took the lives of my family. Miraculously, I was the only survivor. I was just a weak 15-year-old boy, alone in this ruins of that town and at the end of my strength. Just then, a man named Professor Kuseno happened by. He was a professor for justice on a journey to stop the violence committed by the Mad Cyrbog who had attacked my town. I asked for him to perform a procedure to modify my body. Then I was reborn as a cyborg for justice and promised Professor Kuseno that someday I would defeat the Mad Cyborg. Four years passed now. 

You and Ruby were listening to all of it, Weiss, Blake, and Yang were trying not to fall asleep, and Saitama- 

Genos: I was 19, rambling from town to town and exterminating evil. I had defeated countless monsters and evil organizations. But because I had turned up with no clue about the Mad Cyborg, I was spending my days in irritation and impatience. How long had I been chasing phantoms of that Mad Cyborg while ridding the world of evil? And then, one week ago, when that mosquito monster showed up, I had completely let my guard down. I never imagined anything but that Mad Cyborg could defeat me, so without analyzing any data on my opponent, I rushed right into the fight. The result, as you know, was that an opponent displaying immense strength bested me If you, Master Saitama, had not been passing by, she would certainly have killed me. You saved my life. When you did, as Professor Kuseno had once done, it increased my already heavy sense of responsibility. Now, no matter what, I cannot die until I have destroyed the Mad Cyborg. To that end, as a cyborg for justice, I must continue the fight against evil until I find the Mad Cyborg again. I must get stronger! When I saw that one punch by you, I realized that I must study under you. If only I could be that strong. I have an archenemy that I must defeat! This fight isn't only for myself, but I also bear the burden of my hometown and Professor Kuseno. I know I have much to learn. But I need great strength to demolish e- 

Saitama: ENOUGH YOU IDIOT! SHORTEN THIS STUPID STORY TO 20 WORDS OR LESS! 

Yang: (waking up) HUH?! What?! 

https://youtu.be/mLoKIx1t9iA

???: What was that? Mosquito Girl was defeated? 

???2: Well, without sucking blood, she was just a weak insect. 

???: She was just a prototype. 

???2: About that, she was defeated even after absorbing large quantities of blood. And in one punch. 

???: WHAT?! 

???2: A small tracking camera captured the encounter. 

The figure showed the footage to his boss. 

???: Why is he naked? 

???2: Beats me. 

???: Well, he will be a good sample. We will investigate his physiology by force if necessary. Send a messenger to invite him to our House of Evolution. 

???2: Understood. 

Back with our heroes... 

Genos: In other words, I want to become strong like you. 

Saitama: Alright. (Y/N), Ruby, Weiss, Blake, Yang, Genos. 

(Y/N), Ruby, Weiss, Blake, Yang, and Genos: YES SAITAMA/MR. SAITAMA/MASTER SAITAMA! 

Saitama: How old are you? 

(Y/N), Weiss, Blake, and Yang: 20! 

Ruby: 18! 

Genos: 19! 

Saitama: All of you are young, so you have the potential to even surpass me. I'm 25, but I started training when I was 22. 

(Y/N): SERIOUSLY?! 

Saitama: I'll teach you, but it will be hard. Can you handle it? 

Eveyrone: Y- 

Genos noticed something. 

Genos: Something is approaching at high speed. 

(Y/N): H- YEAH! I sense it too! 

Suddenly a giant bug appeared right on the table by breaking through the ceiling! 

Mantis: KEHEHEHEHEHEHEHE! MY NAME I- 

Yang: KAIOKEN! 

Mantis: KAIO-WH- 

Yang punched his head off! 

Yang: ASSHOLE! DON'T INTERRUPT WHEN WE'RE ABOUT TO TRAIN! 

(Y/N): He brought friends too. 

Genos: (Y/N) is right, I am detecting more outside. 

Outside... 

Slug: Our advance warrior Kamayuri is dead. My telepathy can't reach him. 

Frog: WHAT?! But he was really strong! 

You all looked down at them. 

(Y/N): These guys are just wimps. 

Ruby: Yeah, don't worry Mr. Saitama, we will- 

Saitama beat them already. 

Saitama: You ruined my ceiling! 

Blake: How did he- 

Weiss: He really is fast. 

Saitama was then pulled underground. 

Everyone: SAITAMA/MR. SAITAMA!/MASTER! 

Saitama: So this is how a plant feels like. 

Another figure appeared by bursting through a building. 

???: I detect a high level of energy. Are you a cyborg too? 

Weiss: We've got another cyborg here. 

Cyborg: You are not my targets. Get out of the way. 

(Y/N): Not a chance! 

Then a giant lion man appeared. 

Lion: He can't move his hands or feet! Well done, Ground Dragon! 

A tiny mole man came out of the ground. 

Ground Dragon: We don't want you putting up a fight. 

Genos: MA- 

The Cyborg stopped Genos as he blasted him! 

Yang: Seriously, who are these clowns? 

Ruby: I think we don't have time to think about that! 

More of these animal punks started coming in! 

Weiss: Just like Chimera Ants. 

Blake: So, shall we- 

(Y/N): YEAH! TEXAS SMASH! 

Ruby: KAMEHAMEHA! 

Weiss: ICE MAKE: SWORDS! SANTORYU: DRAGON TWISTER! 

Blake: SHADOW BREATHING: FIFTH FORM: SHADOW SPREAD! 

Yang: SHISHI HOKODAN! 

As you guys battled those guys, Genos was fighting the cyborg. 

Armored Gorilla: The Science of the House of Evolution created me. I am Armored Gorilla. Your attacks will not work on me. 

Genos: House of Evolution? What do you want with Master? 

Armored Gorilla: That is none of your business. We destroy any who resist us. I will destroy you. 

The Lion looked at Saitama who yawned. 

Lion: WHY YOU! 

Saitama: It's comfortably cool yet warn down here. I got sleepy, so let me be would ya? 

Lion: HAHAHAHA! You don't comprehend the situation you're in. I will pierce both of your eyes so you can't- 

Saitama: Okay, enough with the jokes. 

Saitama pulled himself up. 

Saitama: If you want to apologize, do it now. 

Ground Dragon: WHAT?! 

Lion: He ... got out? FINE! I WILL SHOW YOU TPOWER OF THE BEAST KING! LION SLASH! 

He began to tear apart a lot of the city trying to get to Saitama! 

Beast King: HAHAHA! That's the law of the jungle! I won't let you get away! 

He bulked up and started to attack over and over! 

Groudn Dragon: WAIT! DON'T KILL HIM! We- 

Saitama: Consecutive Normal Punches! 

Saitama punched him so much that his body tore apeat with his eyes bulging out and his bones and flesh exposed! 

Ground Dragon: 

https://youtu.be/zGF_UpJTkns

Play from 0:06-end... 

(Y/N): Well, that was a good warm up. 

Ruby: Did Genos win his fight already? 

(Y/N): Looks like it. 

You pointed to Genos who had completely beaten Armored Gorilla. 

Genos: Now then, you answer my questions or die. Your choice. 

Amrored Gorilla: You are the one who will die. I am the third strongest of the House of Evolution. You will never defeat the Beast King, he is the second strongest. 

Saitama: This guy? 

Saitama held his eye. 

Blake: Uh ... yeah. That's what's left of him. 

Armored Gorilla soon began to talk normally. 

Armored Gorilla: Uh ... sorry about that. Il tell you everything, please don't kill me. 

Ruby: Wait, you can talk like a normal person? 

Armored Gorilla: Yes. 

Weiss: Then why were you talking like a robot? 

Armored Gorilla: I was trying to sound cool. 

He then began to tell a story. 

Armored Gorilla: A long time ago, there was a young scientist who directed his immense intellect toward making numerous contributions to the world. But the world disappointed him. Peole praised the genius of his mind, but rejected the idea that obsessed him. Instead of developing human civilization, his one dream, was the artificial evolution of the human race. But no one would cooperate. Even as a child, human imperfection dismayed him. Everyone around him looked like animals. He was 15 when he thought of his plan for evolving the human race, to creat a world where he could feel at home. After he turned 70, his plan accelerated. First, he regained his youth. Then he created clones of himself. Together, they performed countless animal experiments before moving on to human subjects. Hec called the laboratory, the House of Evolution, and their experiments gave birth to many new- 

Saitama: JUST GET TO THE POINT! 

Genos: And shorten it to 20 worlds or less. 

Ruby: I ... wanted to hear the rest. 

(Y/N): Acutally, me too. 

Armored Gorilla: R-Right. Our Bos is interested in your body. 

Saitama: I'm not into dudes. 

Weiss: No! He means using your body for his research! 

Blake: Hey Genos, do you know anything about them? 

Genos: The House of Evolution was stated to be a cult for preaching about the coming of a new world. 

Yang: Hmm ... so, those guys, and that mosquito chick come from there? 

(Y/N): Those bastards have got to be stopped! 

Genos: Agreed, we have to plan our attack. 

Saitama: Yeah, let's go. 

(Y/N), Team RWBY, and Genos: NOW?! 

Saitama: Tomorrow is bargain day, so I can't go then. 

Armored Gorilla had an antenna out of his head. 

Armored Gorilla: I better report this to- 

Yang: Hey. 

Armored Gorilla: Y-Yes?! 

He put his antenna away. 

Yang: My buddy here wants to know about an cyborgs that were developed four years ago. Did he destroy any towns? 

Armored Gorilla: I don't know, I'm the only cyborg that was built there in the House of Evolution. 

Yang: Right. Thanks. 

At the House of Evolution... 

Dr. Genus (Leader of the House of Evolution!) 

Genus: WHAT?! Kamakyri, Slugurs, Frog-Man, Ground Dragon, Armored Gorilla, Beast King, and all of the Foot Soldiers were wiped out?! These people took down my elite force of xeteminateing the stagnant human race! 

Clones: Accoring to Armored Gorilla's transmission, they're coming to attack. They could destroy everything we worked so hard for. 

Genus: There is only one thing left to do. We must unleash Carnage Kabuto! 

Clones: WHAT?! WE CAN'T! 

Genus: Calm down, it's just a last resort. With luck, the traps on floors 1-8 will stop them.