On the coast of Foosha Village in the Goa Kingdom, East Blue.
A boy wearing a straw hat stood on a small boat, waving goodbye to the crowd.
"Well, I'm off now!"
He waved to the people on the shore and prepared to row away.
"Wait, Luffy...!"
Luffy turned toward the voice.
It was Makino, the owner of the village bar. She hurried over, clutching a fresh newspaper and gasping for air.
"Luffy, wait! Today's paper... has..."
"It has... a report about Cain."
"Cain!!"
Hearing the familiar name, Luffy's hands snapped back.
They stretched out like rubber bands, crossing the shore in a flash to snatch the newspaper right out of Makino's grip.
Makino was long used to his antics and just let it go.
As Luffy read, his excitement faded into a wince and then to a look of pure pity.
"Cain! How awful... Grandpa really is the worst. Good thing I stayed behind. Being a pirate is definitely better. Don't worry Cain, Ace and I will remember your sacrifice..."
A scar-faced old man with a finger shoved deep up his nose took up the entire front page.
In the background, squished into a tiny corner, lay a pink-haired boy around Luffy's age.
He was covered in massive, cartoonish lumps.
The old man was Luffy's grandfather, Monkey D. Garp.
The pink-haired boy was his childhood brother, Chad Cain.
Anyone else would have missed the kid in the corner, but the villagers had watched them grow up.
They recognized Cain right away.
"Sigh, out of all you brothers, Cain was the only sensible one." The village chief shook his head, though he still smiled as he waved goodbye.
Luffy and his other brothers were set on becoming pirates.
Cain was the only one who actually listened to Garp and joined the Marines years ago.
After Luffy sailed off, the villagers crowded around to read the report.
...
Rewinding time a bit, to the second half of the Grand Line, the New World.
Punk Hazard.
It was once a Marine research base and a World Government prison.
But a massive accident released toxic gas, turning the island into a wasteland.
The lethal gas was gone, but the island remained dead silent as a group of Marines escorted a prisoner made entirely of gas.
The prisoner shrieked, "You think capturing me is the end of it?! The Four Emperors won't let you get away with this!"
Cain held a strange swirly-patterned fruit.
He took a casual bite as he watched Caesar Clown get dragged away.
'Yeah, yeah, I know you have two Emperors backing you, plus a Warlord. We get it,' he thought.
"You brat, what do you think you're eating?!"
BONK!
A massive fist crashed down on Cain's head.
The awful taste of the fruit exploded in his mouth, nearly making him gag.
Ignoring the throbbing pain in his skull, he clamped his hands over his mouth and forced himself to swallow.
He glared up at the old man who had just hit him.
"Cain, if you want a Devil Fruit power, you can find one anywhere! You can buy one, or just ask your grandpa for help! But those are fake experiments made by that Caesar guy. Who knows what kind of side effects they have, you goddamn idiot!"
Seeing Cain actually swallow the thing, Garp lost his mind.
He grabbed Cain by the shoulders and rattled him, then grabbed him by the ankles and shook him up and down, trying to force it back out.
"Gr... grandpa, wait... I'm... I'm fine..."
Garp dropped him and patted him down.
Once he was sure Cain was not dying, he let out a loud sigh of relief.
Cain rubbed his neck and sat on the ground, trying to feel out his new power.
But Garp just grabbed his wrist and hauled him toward the shore!
"Guess I still need to test if you've become an anchor now. Go take a dip."
"Wait, what—"
Splash!
Before Cain could even finish, Garp hurled him into the ocean.
Garp peered over the edge of the cliff. "Hey kid, you alive down there?"
"..."
"Just as I thought. You're sinking like a stone!"
Cain stared helpless as his body sank into the cold water.