Hey, guys! I had to write this down as soon as I thought of it. I had a headcanon awhile back where the MCU and Riordanverse coexisted. This takes place after HoO and Infinity War. The Endgame trailer doesn't matter here becauseI can say so. So yeah. MY DISCLAIMER IS ON MY PROFILE, ADMINS. But since I'm also paranoid, I own nothing. I wish I did.

Being a son of the Big Three, Percy was aware of many things happening in the mythological world. Not small things, but big, major events. Like a god's death, a particularly powerful entity entering the mortal world, stuff like that.

He was having a picnic in Central Park with Annabeth, just hanging out and being in love.

"Only a few more weeks until summer, huh, Seaweed Brain?" Annabeth asked.

"Yeah. Then we have the whole of summer at camp. I can't wai-" Percy was cut off by a stab in his gut. He looked down, horrified that he had actually been stabbed. No wound. No blood.

"Percy?" Annabeth asked, concern etched on her face. Percy knew what this meant. Something was happening. Something big. He turned to his girlfriend.

"Camp. Now." They abandoned their food and jumped into Percy's car. Percy stomped on the gas and they headed for Camp Half-Blood.

When they arrived, Percy pulled the car over. They got out and ran up the hill. The two demigods reached the top and gazed down at the camp. It looked peaceful. The stabbing got harsher. Percy winced. Annabeth grabbed his hand and pulled him down the hill to the Big House. When they arrived, Chiron was waiting on the front porch. He ushered them into the rec room, where the other head counselors were waiting. Percy was surprised to see Frank, Reyna, and Jason along with the centurions of each cohort. Hazel gripped Frank's hand so hard, Percy thought it was going to break.

"Demigods, something is happening. Something big." Chiron said.

"Yeah. It's not good. It involves mass death." Nico di Angelo spoke up. He glanced at Will Solace, reddened a bit, and went on. "I was in the Underworld with Dad and I felt a stab in my gut."

"I felt that, too," Percy said. "It's why we're here."

"I was with Pipes. I can relate to you both, with the stab." Jason said. Nico nodded.

"Not long after I felt it, a great weight landed on me. Not literally, of course. But each time I sense a death, it feels like a five pound dumbbell gets put on my shoulders. This felt like a battleship. Many deaths are imminent."

Seven thousand miles away, in Africa, the universe trembled. A massive hand snapped its fingers, unleashing the full might of the Infinity Stones in a single instant.

"-contact the gods." Chiron said. "We need to figure out what is happening." The smell of sea, ozone, and death permeated the air.

"I'll tell you what is happening." A voice said. Three gods appeared. Hades, Poseidon, and Zeus. Their expressions were grim.

"The Infinity Stones have been used. In tandem." Zeus said.

"Universal carnage is imminent." Hades said.

"It is inescapable." Poseidon said. "Prepare yourselves." And they vanished. The assembled campers were silent. Then they began clamoring at once.

"What the Hades are the Infinity Stones?"

"Universal carnage? Is Ares possessed or somethin'?"

"It's inescapable?"

"Are we gonna die?"

"What do we do?" And so on.

"Guys! Shut up!" Percy yelled. They quieted, murmurs flitting around. "Obviously, something bad is happening."

"It already has." Nico whispered.

"What?" Percy asked, facing the son of Hades. Wide eyed, Nico lifted his hand. It began flaking apart, breaking into ash and dust. His black eyes were filled with fear. He clung to Will.
"Will! Help me! Please!" Slowly, his arm, then side broke apart. He fell. Looking Will in the eyes, he whispered.

"I love you." And was gone. A pile of dust remained with a black sword laying in it. The demigods were shocked. They they rushed outside. The camp was in chaos. Other campers were running around, screaming. Some suffered the same fate as Nico. They broke into dust and were blown away, save for their weapons and gear.

"Frank…" A young voice said. Reyna stared at her arm. She looked at her fellow preator, her eyes filled with terror. "Protect the legio-" and she was gone. A cry came from Percy's left. He whirled around. Jason slowly coming apart, clutching Piper.

"Don't let me go, Pipes. Please. I don't want to go." He fell and broke apart when he hit the ground. His golden gladius shimmered in the sun. Piper wailed.

"Jason!" Desperately, Percy faced Annabeth. No. Not her. He lunged for Annabeth, but caught only dust. Her drakon bone sword clattered on the ground. He stood shakily and faced Chiron. Hazel shrieked. She suffered the same fate as the others. Frank roared and turned into a dragon. He blew fire and flew away. Shakily, Percy looked at his hand waiting for it to do the same.

"What the hell just happened." Percy demanded. The trainer's voice was shaky.

"I never thought… in all my years… they would be used."

"What's they?

"The Infinity Stones." But his words reached empty air. Percy ran away, taxi whistling as loud as he could. Blackjack flew down.

Boss! What's happening? Guido. He-he just-.

"I know Blackjack. Come on. We need to go." Percy hopped on the pegasus and flew into the air.

Blackjack knew where to go. They flew over Manhattan, heading upstate. Eventually, a complex came into view. Multiple building were clustered in a sizable clearing. The largest sported a big 'A'.

Boss… help. Percy looked around Blackjack. The pegasus' hindquarters were dissolving. They were still hundreds of feet in the air. Blackjack wobbled. Percy felt his seat on the back loosening.

Go, boss. Percy shook his head.

"No, Black!"

Man, listen. I'm… I'm a goner. Jump off and try to land in a tree. Don't worry about me. I'll find Annabeth. Good luck, Perseus." And the black pegasus was no more. Percy plummeted through the air. He managed to readjust and fall into a tree inside the complex. Tumbling down, he smacked his wrist on a rock. Pain rippled through his arm. He stumbled to the main entrance. A display winked on. A blue circle appeared, pulsing as if alive.

"Good afternoon, Mr. Jackson. What brings you here?" a female voice emanated from a speaker.

"Need… to see-"

"Got it." The voice said. The door hissed open. A man stood in the doorway. His brown-black curls were graying. He let Percy in.

"Banner. I need-"

"He's farther in." The man said. Dr. Bruce Banner led the son of Poseidon farther into the complex. They finally came to a stop outside a door. It hissed open. Another man looked out. He made eye contact with Percy. There was only one of his kind. A legacy of Vulcan and a direct son of Athena. The only person to combine Rome and Greece in one.

Tony Stark.

Iron Man.

Genius.

Billionaire.

Playboy.

Philanthropist.

Founding member of the Avengers.

Earth's Mightiest Heroes.

"Hey, kid."

"I'm ready."

Perseus Jackson shook hands with Stark, making it official. Percy's expression was grim. His fatal flaw was personal loyalty. Whatever happened to those that got dusted, would be avenged.

One more member was accepted to the most powerful heroes in the mortal world. Now, there was one from the mythological.

Perseus Jackson, son of Poseidon, god of the sea and earthquakes, lord of horses, was an Avenger.

Yay! I finished it. And yes, I did make Annabeth get dusted. Whaddya gonna do? As always, like, comment, subscribe- wait... No, just read and review. This ain't YouTube.