It Runs in the Family

Jason

Jason groaned as the monster of the week threw him through a wall. The monster couldn't be hurt by mortal weapons' as Diana said it and thought that their punches were measly taps. Even Superboy could barely make a dent. On the plus side, the monster also threw Dick and Superboy in at the exact same time, so Jason didn't feel too bad. He was also pretty sure that the only reason he went through the wall instead of against it was because Kon had been thrown with him, so that was something, too.

Still, it freaking hurt.

A dramatic sounding groan from inside the shop made Jason still. Were there civilians? What were they still doing here? They must have heard the fight!

A girl groaned angrily, "I just want to eat my food in peace! Is that too much to ask?"

"Of course it is," a boy muttered, just as frustrated, "We've got unlucky charms Percy and Thalia here."

"What?" Percy (Percy actual Jackson! What was he doing in Happy Harbor? Why did he not leave when the battle started? That idiot!) squawked, "Why are we the only unlucky charms?"

"Think about your parents and when you were born," Nico answered. Percy sighed.

Slowly, Jason picked himself up from the ground. Behind him, monster of the week tore the entire wall off of the restaurant, revealing it and the various heroes trying to take it down. Jason stood up shakily  (there was probably a concussion somewhere). Sat at a table, nonchalant  as can be, were Percy, Annabeth, Thalia, Nico, and a host of other teenagers that Jason didn't recognize.

Percy glanced over, blinked once, and then asked, "Jason?" Jason was going to kill him, no matter what their mother wanted.

Then, out of nowhere, Diana of Themyscira, who had never met Percy sighed and clicked her tongue, "Secret identities, Percy."

"Ah, sorry about that, Di," Percy threw back. Jason gaped from beneath his mask. What other dimension did he end up in? Literally what was happening? He was only gratified by the knowledge that no one else knew what was going on.

"Jeez, Seaweed Brain," Annabeth sighed. Percy just rolled his eyes.

Diana grunted as she flew out of the way of an especially well-aimed tail attack. She glared back at the group, "Are you going to help?"

"Help?" one of the boys yelped, "Are you serious? No way!"

Diana gave them all her disappointed glare, "Get out here and help! It's one of ours! Mortal weapons cannot break it's skin."

A blonde boy groaned, slamming his head on the table in front of him. A pretty girl next to him patted his back in consolation.

Percy growled, "You know what? You've already given away more than you were supposed to. You get to do the explaining in case you're wondering. Get the heroes away. I'll take care of it."

"Want any help?" Thalia asked. Without waiting for his answer, she went back to eating his food.

Obviously aggravated, Percy sighed, "No. It's fine. I've got this one." She waved a disinterested hand in response. Percy rolled his eyes.

More than confused, the heroes pulled back at Diana's request, standing in the middle of the destroyed diner. Jason jerked forward as Percy started moving towards the monster. Diana grabbed him and yanked him back. Jason tried to struggle out of her grip, "Let me go! That's my brother! Percy! What are you doing?"

Percy turned and grinned at him, "You know I've been keeping secrets." He grabbed his hoodie, did something complicated with the strings and then pulled it over his head. The hoodie transformed into a helm, the transformation taking over all of his clothing as shiny armor took over. He tapped his favored watch and it expanded into an incredibly intricate shield that depicted incredible battles. Then he  grabbed that stupid pen of his. He uncapped it for the first time in Jason's memory and... it turned into an actual sword.

"I am so confused," Jason announced pitifully, still hanging limply from Diana's arms. She shifted him so he was held in one arm and then patted him on the head.

Percy strode forward. He paused before the monster and announced,  If you know what's good for you, you'll go back to Tartarus where you belong." Dick mouthed the word 'Tartarus'  incredulously. What was happening?

The monster screamed at him in response. Percy just rolled his eyes, "Fine. Have it your way."

And then he moved. It wasn't necessarily that much faster or superhuman than the moves that Jason saw in the heroes around him. It was just the fluidity, the grace, the ease that he did it that surprised Jason. It was the same kind of movements he saw in Diana. The same  movements he saw in the Amazons. These were the movements of someone who had not only been born to wield a sword, but who had been trained for a  long time to do it properly. Jason was shell-shocked at the thought that his little brother fit in that category. Behind him, Percy's friends continued eating and talking as if this was normal. Maybe it was  (maybe Jason didn't want to think about that).

Percy hacked and sliced at the thing, doing more damage in a minute than the Justice League had done in forty. Even Diana looked impressed and she'd done the most damage (this was, mostly, because her sword actually worked on the beast. It appeared that Percy's expertly wielded pen-sword worked too. Who would have guessed?).

The monster finally caught Percy around the middle and he grunted as he was thrown back. He threw his hand out and a nearby fire hydrant broke. Percy grabbed the water with his mind and used it to cushion him. He promptly went back to fighting the monster while floating off the  ground, standing in the middle of an actual mini-hurricane.

Jason was going to have a heart attack before the day was over.

Percy killed the monster in three minutes. Jason wasn't even jealous he was so confused.

And then Percy just... sat back down. And started eating again. Annabeth brushed a bit of golden dust out of Percy's hair and kissed his cheek. The girl who'd first spoken grunted that Percy had missed a few openings. Thalia griped that she could have done it faster. Jason couldn't even with these people.

It was Dick who found his voice first, screeching, "Are you going to explain that?"

"Diana said she would," Percy answered without even looking up.

Diana smirked at Percy before turning to the heroes and announcing very seriously, "You know from my own past and race that the world of Greek mythology is true. As such, there are also demigods. This group of people are this generations most famous demigods. The Heroes of Olympus most of them are called. Percy is the demigod son of Poseidon and has been leading the other Greek demigods in wars and saving the world since he was twelve years old."

"Oh my gods," Percy said, beet red, "Please don't embarrass me." Jason wondered why he'd never noticed that Percy said 'gods' before. Wilful ignorance, probably. He still felt a bit faint.

Jason sat down hard in the concrete dust. Percy peered at him in concern. Jason looked over to him, "When we first met, you said that you had many siblings. You actually meant you had thousands of years worth of siblings. And you still say that I'm one of the highest on your list  of favorite siblings."

Percy's eyebrows drew together in confusion for a moment before he started laughing and laughing. Eventually, Jason joined in. Percy was definitely his favorite brother.