Y/N was out on his own looking the city. He tends to go out on his own from time to time when he's had enough of Shigaraki and his whining. As he sits on the ledge of a building eating a pretzel, he takes in the breath of fresh air. 

Y/N enjoys his time out when it's just himself. It's a nice scenery and it's just him along with his thoughts and the people down belong look like ants going about their business.

As Y/N finishes his pretzel and wipes his hands, he grabs onto the sides of the fire escape and slides down until he reaches the ground. 

As he makes his way out of the alley, Y/N puts on his mask and places his hood on his head to hide his face. As he walks down the street, he spots someone, he didn't think he'd ever see again.

Y/N: Tsubasa....

Tsubasa was one of the many people that bullied Y/N when he was younger due to him being Quirkless. He had dragon-like wings for a quirk which allowed him to practically fly. Y/N silently follows the boy as he's oblivious to the fact that Y/N is following him. 

For what seemed like hours, Y/N silently followed behind Tsubasa to his home. As the boy entered his house, Y/N started at the house for a few minutes before making his move and walking up to the door. He started covering the peephole and knocking.

Tsubasa couldn't see who knocked and as Y/N knew, he was stupid enough to open the door and see who it was. As he did, Y/N punched him in the face, making him fall back.

Tsubasa: Ow! What the- 

Before he could scream out or yell, Y/N grabbed him by the neck and lifted him up and started choking him.

Y/N: It's been a while, abusive scum...

Tsubasa: (chocking) W-Who the hell are you?! 

Y/N knew that Tsubasa wanted to know who was attacking him, so he pulled his hood back and took off his mask to reveal his face, shocking Tsubasa.

Tsubasa: (chocking, shocked) Y-Y-Y-Y/N?! But... you're...supposed to be....dead...

Y/N: Well you know what they say. What doesn't kill you, simply makes you stronger.

Tsubasa wanted to ask Y/N more questions, but because he was losing air, he couldn't.

Y/N: You're part of a group of people who are on my shit list. You made my life harder, and for what? Because you had a quirk and I didn't? Well, now you'll know what it's like.

Before he could question him about what he means, Y/N's eyes glow red as what seems like red energy comes from Tsubasa's body and flows into Y/N.

He tries for fight back against whatever Y/N was doing to him, but it was no use. Whatever Y/N was doing was draining his strength and left him weak. 

It didn't take long for Y/N to finish as he throws Tsubasa away. The energy flow slowly disappeared as Y/N's eyes returned to normal.

Y/N: Woah.... That's a rush.

Tsubasa: (weakly) What did....you...just do to me....?

Y/N: Hehe, it was my first time, but I managed to pull it off.

As Tsubasa mentality questioned himself, his eyes widen when Y/n suddenly grow a pair of dragon-like wings from his back, Tsubasa's wings.

Y/N: Your quirk's pretty useful, I think I'll keep it.

Tsubasa struggled to get up as whatever strength he had before was faded.

Y/N: You look so pathetic, trying to get up and all.

Y/N turned his back towards him as he headed for the door. Grabbing the doorknob, Y/N turned back to look at Tsubasa.

Y/N: Let's see you bully anyone now. 

Have fun being Quirkless!

With that, Y/N leaves Tsubasa's house and heads for the alleyway. As he enters, he makes a good enough distance as he stretches his arms back and forth as he prepares himself.

Y/N: Okay! Here we go, let's test out this new quirk.

Y/N uses his new found dragon wing quirk, to go from the alleyway into the air as he flys around for a bit to get a feel for this new quirk. It doesn't take long for him to enjoy the feeling of flying around, but his enjoyment what cut short when his phone began to ring. So landing on the ledge of a building, Y/N perched on the ledge and answered his phone.

Y/N: (sigh) What do you want now?

Shigaraki: Where are you?

Y/N: Uhh, just out and about. Why?

Shigaraki: Because of our meet with the Hero Killer. Or did you forget?

Y/N: Nah I remember. I'll be there in a second, don't get your hands bundled up.

Shigaraki: What the fu-?!

Y/N: (hangs out) Idiot. (phone rings again) Yes?

Beros: It's Beros. We've got the Nomu. 

Y/N: Good. Warping.

A black ooze appeared in front of him as Beros came through it with the experimented Nomu and a muscular hulking man with bleach white skin, black markings on his face and forearms, and a single row of brown spikes running down his spine. He has a relatively small head, with beady orange-yellow eyes and a wide set of teeth. On Leviathan's fingers and toes are spiraling red appendages. There is also a set of "tubes" with the same appearance stemming from his back and connecting to his head. He wears torn black plants with a brown belt.

Y/N: The Nomu that was with Shigaraki. You've finally caught it. 

Beros: It wasn't difficult. With Leviathan's strength, we broke their blockade before they could transport it to Tartarus. Though, I don't understand you want that Nomu. 

Y/N: I didn't. What I want are his quirks. 

Y/N walked towards Nomu and placed his hand on its face as his eyes glowed red and the same red energy comes out from Nomu's body and flows into him. 

Nomu's body eventually started changing into a dead human body which fell down on the floor as Y/N was finished taking its quirks. 

Beros: (surprised) You can take other people's quirks now? 

Y/N: Indeed. The first time I tested it was a few minutes ago, and I've stole his dragon-wing quirk. 

Beros: Amazing. (looks at the former Nomu) So, what do we do with him? 

Y/N: Dispose of him. He's useless to us now that he's dead. And head back to the hideout while you still can.

Beros: As you wish.

Leviathan growl in response as he grabbed the former Nomu with his large hand. Y/N stretches out his dragon wings and sets out to flying towards the hideout. It didn't take long for him to arrive at the hideout as he entered the door, he saw Shigaraki sitting at the bar with Kurogiri behind it.

Shigaraki: Finally, you're here.

Y/N: Aww, did I keep the little baby waiting?

Shigaraki: Hilarious... Where were you?

Y/N: Oh, just out, getting something new.

As Shigaraki raised his eyebrow, Y/N didn't need to say anything as to answer his question, one of Y/N's new found quirk, dragon wings, protrudes from his back, shocking both Shigaraki and Kurogiri.

Kurogiri: You have wings now?

Y/N: Not only that, but I also attained Shock Absorption and Super Regeneration from the experimental Nomu.

Shigaraki: Where did you get those...?

Y/N: Oh, you know. It was a "gift" from an old friend.

As Shigaraki stared at Y/n with some anger in his eyes, the TV scene behind Shigaraki starts to speak. The voice behind it was All For One.

All For One: Well done Young L/N. It seems you've taken your first quirks. Very impressive.

Y/N: Hehe, thanks old man. You know, I didn't think it would work at first, but I managed to pull it off.

All For One: You're progress with my quirk is impressive, but you should develop the power you have first. Channel it as it was your own.

Y/N: (sighs) Yeah, sure...

As Y/N rubbed his neck, he was kinda annoyed that despite him having All For One as his quirk for 10 months, his mentor still calls it his quirk. 

But Y/N doesn't say anything and just keeps his thoughts to himself. Y/N then throws himself over on the couch that's in the corner and lets out a heavy sigh.

Shigaraki: What's wrong? Sad that you didn't get Master's applause?

Y/N: I'll fight you.

Shigaraki: That's one fight you won't win.

Y/N: Nah, I'd win.

Shigaraki: Oh really?

Shigaraki and Y/N both get up and square up against each other as they get locked into a stare down.

Kurogiri: Calm yourselves boys, we've talked about this. You're are allies, not enemies.

The two stand in place for a bit longer before separating and going back to where they were.

Shigaraki: You missed the U.A sports festival.

Y/N: And why would I give a shit about that?

Shigaraki: One of those brats that was at the USJ that also killed nearly me won. 

Y/N raised an eyebrow and Shigaraki tossed him some pictures that landed in the coffee table. As he looked through the pictures, he stopped when he saw five familiar faces, and three in particular made him freeze.

Y/N: (quietly) Arc... Wanda... Izuku... Who won? 

Shigaraki: The brown haired one with the lightning speed quirk. However, the blonde haired guy with his explosion quirk caught my interest. He maybe at a school for heroes, but with the way he is, he's more villain material.

Y/N: You have no idea....

Shigaraki: Huh?

He puts the pictures together as he stands up and hands them back to Shigaraki.

Y/N: Nothing. When is the Stain coming?

Shigaraki: Kurogiri, would you be so kind as to bring the Hero Killer here?

He gives Shigaraki a nod as he uses his quirk to make a vortex at the entrance of the hideout. After a couple of seconds, the man they're looking for coming walking through, the infamous Hero Killer: Stain.

Y/N: Wow. Looking at his picture or on the news is one thing, but actually seeing him in person is something else.

Stain: Where am I? And who are you?

Y/N was about to speak, but Shigaraki beat him to it.

Shigaraki: We're the League of Villains and you're in our little hideout.

Stain: Ah, now I get it. You must be the ones who attacked U.A. You want to recruit me to build up your little group again.

Shigaraki: Yeah, it'll be great. You've got so much experience.

Stain: And what is your mission?

Shigaraki: For now? I really just wanna kill All Might. I like to destroy anything that pisses me off, like this little brat right here. Game Over.

Y/N: I pissed you off and I'm still here. What's up with that man?

Stain: I was a fool to think that you could offer me anything. It turns out, you're the type of person I hate most in this world. The goals of your league are those of a child. What meaning is there to killing if you don't have real convictions?

As Stain reaches for his blades, Kurogiri gets worried about the situation.

Kurogiri: (thoughts) The Hero Killer: Stain... Unlike Y/N L/N, Tormua Shigaraki cares only about want and violence, so we brought this man in to guide him. Perhaps we made a mistake.

Kurogiri then turns to the TV.

Kurogiri: Master, should I step in?

All For One: Let it happen. It's possible this is the only way he'll learn anything. He needs to think about the ways he must grow, how he can mature. Only then, will he reach his potential.

Stain quickly attacks the three villains, throwing his knifes at Kurogiri and Y/N, while stabbing Shigaraki in the shoulder and pinning him to the ground. 

When Stain throw his knife, it nicked Y/N's cheek. As he went to strike the Hero Killer, he suddenly froze where he stood.

Y/N: W-What?! I... c-can't... move...!

Beros: (comes through the door) Y/N! 

Beros used her quirk to transform her left thumb and pinky finger into the two ends of an archery bow before she fired an arrow at Stain which he cut through it with his knife. 

Leviathan jumped and thrust his a large fist at Stain which he jumped over and landed a couple feet away from the villains. 

Stain: So you want me to be apart of your crumbling little league? But you won't accomplish anything if you don't have conviction and desire. Without those, you'll always be an aimless weakling. Achieving nothing. That's how you got here.

Shigaraki: Hey now, you're being a little rough aren't you? Kurogiri, take this guy back.

Kurogiri: I'm sorry I can't move! It must be the hero killers quirk at play.

Y/N: (thoughts) What's this guys's quirk? Paralysis?

Stain: The word hero has lost all meaning in this society. The world is overrun by fakes and criminals like you who chase petty dreams. They must all be purged.

He goes to stab Shigaraki, but he catches the blade and uses his quirk to decay the blade.

Shigaraki: What do you think you're doing? If you touch this palm, I'll kill you. You sure talk a lot hero killer. Conviction? Maybe I don't have anything as loaded as that. If I had to choose a desire though, it'd be killing All Might. If this world wants to worship trash like him I'll destroy their beloved symbol of peace and then crush them while they're in shock.

Shigaraki goes to attack Stain, but he's quick enough to move back from his swing.

Shigaraki: The last of my injures was just about finish healing and now this. You should learn not to play with knifes. We don't have a healer in our party.

Stain: I see your nature. It seems our goals fundamentally oppose each other. However, this wasn't in vain. We agree that we need to destroy the present.

Shigaraki: I'm over this. Leave, drop dead. I'm the kind of person you hate most right?

Stain: I was testing your motives. People always show their true colors while on the verge of death. It's abnormal, but there is desire. A warped sprout of conviction inside. How will it bloom in the end I wonder. Maybe I'll let you grow, and if you don't turn out well I'll take care of you later.

Shigaraki: You think you can get rid of me?

It's then when Y/N and Kurogiri are able to move once again. 

Beros: (came over to Y/N) Are you alright? 

Y/N: I'll be fine, my body's able to move again.

Kurogiri: I'm free.

Shigaraki: Kurogiri, Y/N, someone as crazy as this will be nothing but a problem for the league of villains.

Kurogiri: Please, reconsider. This man will be a great asset if he joins us.

Y/N: He's right. His record for taking down heroes is flawless, unlike a certain someone.

Stain: My business here is done. Now, you will return me to Hosu. There are still several false heroes I must attend to there.

Kurogiri listens to Stain's request and he opens a portal back to Hosu city. As Stain's about to walk out, he stops and he turns back and looks at Y/N.

Stain: You....

Y/N: Huh?

Stain: What is your mission?

Y/N: My mission...?

As Stain asked Y/N this question, he narrowed his eyes at the thought of this question.

Y/N: (thoughts) My mission huh....

Little Izuku: I wanna be a hero like All Might who saves people with a smile!

Stain: Well?

Y/N: My mission......is none of your fucking business.

Stain just huffs and walks through the portal back to Hosu. As the vortex closes behind him, Shigaraki starts to complain like always as Y/N heads towards his room.

As he throws himself onto his bed, he stares at the ceiling for a bit before looking over to his nightstand. Reaching over towards it, he opens the drawer and pulls out a photo, it was of him Arc, Wanda, and Izuku as kids.

Y/N: My mission huh... I wonder, Izuku, Arc, Wanda, what is your mission?

Chapter 7 ended. 

I hope you guys like that part with us meeting the Hero Killer. Next up will be the attack on Hosu with Arc, Izuku, Iida, Shoto, and Robbie fighting the Stain. 

Let me know what you guys think or if you have any ideas for it at the comments below, peace out and enjoy!