Disclaimer: I do not own One Piece... that is all!

Pairing: slight Luffy/Ace (or actually, you can take it as you will for this one)

Notes and Warnings
-AU.
-Marine!Ace and alive!Sabo (for now anyway...)
-Angst... again (I'm sorry, orz...)
-This chapter probably wasn't written all too well... beta reader, what is that? lol
-I suck at coming up with titles...

Summary: It was a fate that none of them could have expected. What was he to do when faced with the decision of choosing one brother over the other?

-In a Different Life-

"Here I come, Sabo!" Luffy yelled, running up the stone bridge leading towards his brother with a confident grin. He barely registered the cheers of the rebels behind him as he continued on for the kneeling prisoner on the center stage of this war.

He did however stop abruptly as the middle of the makeshift stone bridge he was travelling across suddenly exploded in a burst of flames, a single man jumping through the large hole created in the aftermath. Luffy's eyes widened in surprise and horror as he realized just who it was.

"Did you really think I'd let you reach Sabo that easily?" the man snarled, his body surrounded by a swirl of red flames waiting to torch any foolish being that dared get close.

"Ace...?" Luffy took a step back from him, not because he was scared of fire (although admittedly, being melted into a hot pile of rubber didn't sound all too appealing), but because of the harsh glare he was receiving.

No matter what stupid things he'd done in the past-and trust him, he pulled a lot of dumb shit before-neither one of the two he called "big brother" had ever looked at him like that before. He saw anger, disappointment and sadness all mixed into those dark orbs, and all aimed directly at him. It made Luffy's stomach turn.

Several seconds passed between them in silence, neither one making a move forward. It was as if time had stopped for them, all the battles and screaming of dying men on both sides fell on deaf ears as the brother stared at one another, both of them fearing what would happen should they truly face one another on opposite battlefields.

"What do you think you are doing, Vice-Admiral Ace?" the voice of Fleet Admiral Sengoku came up from his place on the excution platform. It was enough to break the moment between the two on the bridge and make Ace turn upon hearing his name called. Sengoku merely gave him a stern look in return, "Hurry up and deal with the enemy"

"Ace, don't! It's Luffy, dammit!" Sabo screamed, trying to get through to the other.

For a second it seemed as if Ace wouldn't heed to his superior's commands as he stood there looking away quietly. But as he slowly twisted back to face his little brother, Luffy knew the worst thing he could ever imagine had come to life. Ace, his big brother-the one he looked up to and loved-was going to fight him. And it tore the boy up inside.

"Well you heard him Luffy, if you want to get to Sabo..." in one quick motion, Ace had discarded his marine coat while the fires of the Mera Mera no Mi expanded intimidatingly around him, "You're going to have to go through me!"

Luffy couldn't belive this was happening. He was going to fight Ace? He'd done it before but this wasn't like when they were children and challenging each other to mock duels in hopes of becoming stronger. The two of them now were strong enough to be considered a man worth 300 million beli and Vice-Admiral of the marines. It would be a fight to the death.

They were going to try to kill each other? No. No he doesn't-

"I don't want to" Luffy uttered with a shake of his head.

His response earned and scowl from Ace. Obviously it wasn't what the other wanted hear.

"Are you stupid?" the fire user shouted, his fists clenched tight as he glared hard.

No.

"What do you mean, 'I don't want to'? This isn't a game, Luffy!"

No, please.

" You're a pirate, I'm a-"

"Don't say it!"

"I'm a marine! And if you really want to save Sabo...!" Ace paused.

Luffy looked up to see Ace's expression hidden by his favorite orange hat. He wanted to see his brother's face. He wanted to know just what was going on through his head. He wanted there to be someway things could go back to how they were before Ace left the island-left him - to become part of the navy and abandoned their promise of sailing the seas as free men. As pirates.

He felt his heart sink when Ace finally lifted his head.

"You understand, don't you?" Those dark eyes he remembered to be so full of life now stared blankly at him. It was as if he didn't even know who the man standing in front of him was anymore.

How had things come to this?

-End-

So fanfics are all about "what if"s right? Well people are still speculating about how Sabo survived and honestly I want to agree with them but then this little idea popped in my head and well...
Hope it's not too confusing, it's just what I was thinking what if Sabo really were alive and decided to return to his brothers after the whole 'almost getting killed by the Celestial Asshole with PMS' ordeal. I'm a sucker for angst so I then got to thinking "what if then Ace left the island with Garp to become a marine because of it?" and BAM this monstrosity was born xP