Monkey D. Luffy was many things, he was excitable, he was strong, he was loyal, he was a bottomless pit for food and he was watching unable to do anything as his crew was decimated by Blackbeard. He tried to rush to them but he could not reach them in time hen it was his turn. After watching as his crew was killed Luffy fell to his knees and stared blankly at their bodies. He didn't say anything or even react as Blackbeard picked up one of Zoro's swords, walked towards him and chopped off his head.
...
Luffy found himself on a giant floating rock flying threw space. In the middle of the rock was a tree bigger than any he had seen before.
"Interesting isn't it" a voice came from behind him. "It's known as the dimensional tree. It's branches connect to a different dimension and as there are infinite dimensions there are infinite branches.
Luffy turned around and saw a young man standing there looking only nineteen years in age, wearing torn cargo pants and a plain white shirt.
"Who are you? Where am I? Luffy asked sullenly.
"I am known as Lord Traveler and how would you like to try it again? Live again and try and save your friends? I can send you back in time if you wish" Lord Traveler said calmly.
"I'll just lose them again" Luffy said surprisingly with no confidence.
"Perhaps" Lord Traveler said "or perhaps you won't. But anyway I will be changing things around. First of all you will no longer have the gum gum fruit but a different devil fruit and second I will give you the Alpha Stigma an ability that will help you greatly though you will have to find out how to use these two powers on your own" the man smirked.
Before Luffy could say anything he, Lord Traveler, the rock and the tree disappeared and there was nothingness.
...
Luffy opened his eyes and instantly forced himself to vomit as one of the most horrible tastes in the world assaulted his tongue it almost tasted like his devil fruit.
"Shit Luffy did you eat the fruit in that box?" a familiar voce asked. Instantly Luffy was grabbed by the ankles and forced upside down "spit it out. Now make sure everybit is out" the voice yelled.
Suddenly something happened and he fell out of the person's hands looking around he saw he was in Makino's bar, with Shanks and his crew from when he was seven but at the time he was more worried about the fact that his feet and legs had no bones in them.
"WHAT THE FUCK!" he and the pirates screamed.
...
The years after that were great for Luffy. Thanks to his knowledge he was able to save Shanks's arm and Sabo didn't die. He spent the time experimenting with his new devil fruit and realised that he would have to adjust his fighting style as his past one required him to literally throw his rubber body around. But his new devil fruit was more close range than his old one.
He made sure not to tell anyone else about the future and hid his Haki control so as not to scare anyone though Luffy was sure Shanks and his Grandpa were suspicious. Everything was going well and eventually he found himself standing in a marine base infront of a prisoner.
"Join my crew" Luffy said seriously.
"What?" Zoro asked shocked.
"I run a pirate crew and I want you to join it" Luffy said grinning.
"Heh forget it. I will never stoop to being a pirate" Zoro sneered.
"I heard Hawkeye is a pirate" Luffy said with a smirk.
"So what?" Zoro yelled. "I'm not a pirate i'm a swordsman."
"Then be a pirate swordsman" Luffy grinned he really missed teasing Zoro.
"JUST LEAVE ME ALONE" Zoro roared.
Luffy rolled his eyes. He already knew what was going to happen so he may as well just wait and save Zoro before he dies like last time. Come to think about it most of his crew joined by him saving them in some way, strange.
Luffy casually walked away from Zoro whistling Binks's Sake to himself.
After an hour of wandering around town he realised that it was time for Zoro to be executed soon and as such made his way to the marine base.
Casually walking through the front door Luffy knocked out any marines he encountered looking for the idiot's room.
The room was as lame as he remembered and Zoro's swords were where they were last time. Picking them up Luffy looked out the window and saw Zoro was about to be shot.
"Shit" Luffy cursed before jumping out the window landing in front of Zoro. Not having enough time to use Haki he used his devil fruit powers to expand his rips and turn his bones into steal.
"This is going to hurt" he thought as bullet after bullet slammed into him. They didn't pierce through his bones so he was not seriously harmed but his skin and muscles were injured.
"What the hell are you?" Zoro yelled.
Luffy grinned at him trying to ignore the pain "i'm your captain" he grinned.
Zoro snorted "fine then captain hurry up and release me."
Luffy quickly moved and cut Zoro's bonds before handing him his swords.
"Fine i'll join your crew" Zoro announced "but if you get in the way of my ambition then you are going to regret it."
"Which is?" Luffy asked.
"To be nothing but the world's greatest swordsman."
"Sounds perfect the pirate king deserves nothing else on his crew" Luffy replied grinning wide.
"Kill them" ol' axe hand yelled.
The marines charged "i'll handle this" Zoro grinned walking forward. Almost instantly the marines were down on the ground and axe hand was behind Zoro about to hit him over the head.
Bone Spear Luffy charged forward and blocked the axe with the two bone spears protruding from the back of his wrists. "Is that all you've got?" he mocked.
"So you have eaten a devil fruit" axe hand stated. "too bad what matters the most in life is rank. If you have a high enough rank then you have power" Axe hand roared.
Luffy rolled his eyes "i'm a captain too you know" he muttered.
Axe hand ignored him and slashed at Luffy with his axe repeatedly each slash effortlessly being blocked.
"This is boring" Luffy yawned. "I guess I should end it." Luffy retracted the bone spears and twisting on his left foot he kicked Axe hand with his right sending him flying out too the ocean. The ocean that was several miles away.
"What the hell are you?" Zoro gaped.
"You're captain" Luffy grinned.
"But those those bones coming from your arms."
"Oh those. When I was younger I ate the Bone Bone fruit which enables me complete control over my bones" he replied as if it was no big deal.
"Oh is that all ok that makes sense... WAIT YOU ATE A DEVIL FRUIT? THEY ACTUALY EXIST?" Zoro shouted.
"Duh" Luffy said walking away from Zoro back to the town to get some food. He really missed teasing Zoro like this.