A funny idea that popped into my head that I couldn't not write. Enjoy.

It was time.

One for All marched into his team's base, his gaze locked forward with grim determination. In the main meeting room the seven other members in his team, the Musketeers, were already seated in a wide circle.

It was a dingy base, and the main meeting room was no exception. The walls were made of dirty concrete with a few ancient light fixtures on the ceiling. The edges of the room was home to several haphazardly placed tables covered in papers and support tech. It wasn't the nicest of team bases, or the best organized, but it did its job.

One for All made eye contact with them as he walked in. Second (referred to as such due to his and One for All's shared love of Doctor Who along with a little incident involving One for All's quirk), Miichirou, Hikage, Banjo, Nana Shimura, the eldest and one of the earliest official heroes, and finally Toshinori Yagi. Youngest member of the team and the first official hero with no quirk.

Shimura's friend, close ally, and almost-member of the team Sorahiko Torino was also there, leaning against the wall in the back corner of the room.

They mirrored One for All's grave expression.

"I suppose you're wondering why I called you here today," said One for All.

"You said your brother was calling us out," said Nana.

"And that we might finally have to face him, once and for all," said Toshi.

One for All nodded to his young comrade's question.

Despite the determined expression there was a note of fear in his voice. It made sense. As capable as he was, Toshi still had no quirk while his brother was one of the strongest quirk users who ever lived. Unless you had advanced weapons or one heck of a plan, there was only so much you could do with just the human body.

Decades ago, the mysterious powers now known as "quirks" first appeared. In the ensuing chaos, many quirk users rose up, like heroes out of comic books, to protect the innocent from those who used their quirks to hurt them. The government sponsored these brave individuals, creating the first "Pro Heroes".

Nana and Sorahiko were two of the first of these heroes. Izuku and his brother had been fascinated by them ever since they saw a video of the two stopping a group of villains. Sorahiko leapt into danger displaying no fear. Nana smiled and reassured the civilians that everything was going to be ok, before cowing a villain with only a stern glare and the beaten body of his partner as a warning.

Then there were those who rejected those ideals and used their quirks for their own gain at the expense of others. Villains.

One for All's own brother was among the worst of them, using his power to take and give quirks to make others submit to his will. He had no friends, only servants. By the time he was a legal adult, he'd become a powerful crime lord. Since then he'd only gotten stronger. Now the entire criminal underworld knew him by his villain moniker, All for One.

One for All refused to submit to his brother's will and for that was imprisoned.

After his brother gave One for All a power stockpiling quirk (which fused with another latent quirk One for All already had), he escaped and founded a team of fellow heroes dedicated to bringing his brother down.

Now it seems All for One had decided to end their little rebellion.

One for All took in a deep breath. "I went to check on our public mailbox and found this," he pulled the card out of his pocket and held it up with the envelope it had been sent in for all to see. On the back of the envelope One for All's first name was neatly written in unfamiliar handwriting.

"What's in the card?" said Sorahiko.

"It claims to be a wedding invitation. It has a time and place for a relatively out of the way chapel and asks me to confirm if I'm coming." One for All looked at the card again. "The supposed groom of this wedding is my brother."

"And the bride? Is it anyone we know?" said Daigoro.

One for All shook his head. "No. I've never heard of her. If she's even real she's probably just one of my brother's many underlings."

"So, are we going to accept?" said Nana. "Are we even ready to face him?"

"And should we really let All for One pick the time and place of our fight? In my experience the one who chooses the battlefield often has the advantage. And your brother had that enough as it was," said Toshi.

"Look I know it's risky," said One for All, "But we haven't even been able to find my brother in years. Every minute we wait he can steal more and more powerful quirks. Based on All Might's investigations with the police, he's already one of the biggest crime bosses in the nation. If we let this pass, we might not get another chance."

One for All sighed. "I know letting your enemy choose the battlefield is a bad move. But this may be our only chance. I say we learn everything we can of that location, and try to come up with the best battle plan possible. In the meantime, we call in every hero we can, have Toshi bring in as many cops as his influence can muster, and bring an army so strong and well prepared that even my brother won't be able to stop us! If my brother wants a fight, I say we give him the fight of his life! Who's with me?"

One by one, the other Musketeers nodded. "Make the call," said Hikage. "Tell him we accept."

One for All nodded, took out his phone, and dialed. The phone started ringing

Hisashi took out his phone. He didn't recognize the number. "Excuse me Inko, I should take this," he said. His wonderful fiancée smiled and nodded. Hisashi wandered into the hallway in case he had to take this call somewhere a little more private and accepted the call. "Yes?"

"I got your call-out," a very familiar voice said over the phone. "We accept."

"Little brother?" said All for One. "What are you talking about?"

Since their…estrangement (i.e. His brother completely overreacting to that nice safe bank vault All for One got for him to live in and raising up an entire team of heroes specifically to kill All for One like the melodramatic child he was) they had spoken only once or twice, and that was mostly battlefield banter. The closest thing to them actually communicating was Inko forcing All for One to write an invitation for his brother to their wedding, but given that he'd "forgotten" to send it there was no way-

"Don't play games with me. We received that fake wedding invitation you sent and-"

"How did you get that?! I made absolutely sure it wasn't mailed!" said All for One.

At this moment Inko popped her head into the hallway and declared with a bright smile, "Oh I noticed you forgot to mail your brother's invitation Hisashi. So I did it for you!"

"You did what?!" said Hisashi.

"You did WHAT?!" said his brother.

"I'll let you two catch up. Have fun!" and with one last smile that showed she absolutely knew what she did, Inko popped her head back around the corner.

Hisashi lifted the phone back up to his ear.

"You're telling me you're actually getting married and weren't going to invite me?!" said his brother, "You DICK!"

Hisashi sighed. Of course, he'd have to put up with this. He couldn't get away with anything these days… "Well no offense," he said moving into another room and activating a quirk to keep Inko from overhearing, "But the last time we met you tried to kill me!"

"Because you became a crime lord and cult leader and oh yeah, locked me in a bank vault!"

"Are you still on about that?"

"Yes! I am still mad about you locking me in a vault! Do you have any idea how bad that is for someone's mental health?!"

"It was your fault for being so reckless!"

"Yes, locking me in a vault for being in the slightest danger from life was a totally appropriate response, not at all the actions of a controlling nutjob."

"Says the person who routinely throws himself into danger because he thinks he's a superhero from some comic book!"

"Pot meet kettle Mr. Supervillain!" said his brother.

"I can't believe we decided we'd name our child after you if we had a boy," Hisashi muttered as he rubbed his temple.

"You did?!" His brother didn't even try to hide his excitement.

"I'm reconsidering it!" Hisashi conveniently left out that he needed Inko's approval to do that. And that she really liked the name.

"Jerk!"

"Brat." Hisashi said. Then he realized, "Oh no… I never intended to mail it, so I invited the rest of them too," he put a hand over his face.

"You did? Wher- Oh wait there's a postscript. 'P.S. You can bring that pack of idiots you waste your life with if you must'?! You can't talk about my friends like that!"

Hisashi rolled his eyes. "Are you coming or not?" Please say no, please say no, please say-

"Of course I am! I wouldn't miss it for the world! And I'll try bringing the others too!"

Of course he said yes.

Hisashi groaned. "Fine. Please try not to kill me. Inko will murder us both if we ruin her big day."

"Fine. I won't try anything if you won't."

"Deal." Hisashi hung up and tried to nurse his growing migraine.

One for All turned back to his friends. "Hey guys, did you hear that?! I'm getting a sister-in-law!"

None of his team said a word, being too busy staring in a mix of disgust and abject horror to say anything. Except for Sorahiko. He was slamming his head into a table.

Hope you enjoyed! This is probably my craziest idea yet! Reviews make me smile!