Disclaimer: I own nothing recognizable from One Piece.
Author's Note: Spoilers for Luffy's past and the Marineford arc. I was depressed over…recent story developments. If you couldn't tell. :P
Gone
They had led very different lives up till that point.
Sabo had known parents who cared more for rank and wealth than for their son. Ace had known a world that would deny a child the right to live for his parenthood. Luffy had known a grandfather who believed in tough love, a pirate who had given up an arm for his life, and a village that was amused to let him do as he pleased.
If they had anything in common, it was that they had never truly known a friend, or felt truly loved by a family. The solution was simple, really: they themselves became a family.
From that point, though they lived apart from most other people except for their excursions into the slums of Goa to steal food, they knew what it meant to be truly happy.
Ace and Sabo knew that they gained more from their little brother than just happiness. Up until then, they had had even less of an idea of what it meant to love and be loved than Luffy. But Luffy was little and weak. He cried at the slightest pain, though he tried so very hard not to let them see his tears. He followed them around constantly and looked at them with adoring eyes.
Luffy was irritating as nothing and no one else could have been, and he couldn't even defend himself properly. Ace and Sabo scolded and trained him, and by the time they recognized how much they loved him, either would have laid down his life for Luffy a thousand times over.
Luffy was irritating because he was so helpless. Yet his stubbornness made that helplessness adorable and lovable. Luffy was constantly kept in the sight of one brother, if not both; he had a knack for getting himself in trouble, which was badly matched up with his weakness.
When a gator had swallowed Luffy, Sabo and Ace were on the gator within the same second, slitting open its throat and feeling relief like they had never known to see that Luffy was still in one piece. When Luffy fell off a tree or a cliff, there was always a hand, or two, that instantly reached out to grab him by the scruff of the neck.
Ace and Sabo found that they didn't need Luffy to be strong to love him. They loved him for who he was, and nothing was ever going to change that. They loved that even in a crisis, Luffy could laugh and look to them with wide, trusting eyes. They loved that they were the only ones Luffy wanted to cling to when he cried. They felt truly loved and needed for the first time in their lives, and neither of them took it for granted. They loved Luffy all the more.
And Luffy himself, for the first time, thought he understood unconditional love.
As for the love shared by Ace and Sabo…they were alike in many ways. They had long been companions. But it had been the shared responsibility of Luffy that had helped the friendship between them grow further into a brotherly love.
The world that Ace and Sabo worried about on Luffy's behalf was a cruel, terrible place. Indeed, it hunted them down one by one for dreaming the dreams they dreamed; for daring to exist.
Finally, Luffy is the only one left. He never realized how much he depended upon his brothers' existence until he received news of Sabo's death. He never knew how much it hurt to be truly alone until Ace died in his arms.
Now, in the middle of some forest in the wide world, he thinks of the days they lived together in the woods. He wishes that they'd never dared to dream. Pirates? Pirate Kings? How had they dared? They were no more than three little boys in an unforgiving world full of cruel people who wanted to control everyone else. Why did they not just remain in that forest near Goa, living as small-time bandit outlaws? Why did any of them ever set out to sea?
Luffy was the weakest, yet he is the only one left. If only one of them could live, why couldn't it have been Ace? Strong, dependable, knowledgeable Ace—everything Luffy is not, and still so much more. If any of them was to be Pirate King, that one would have been Ace. Luffy sees that, now.
Luffy also sees that he had been looking forward to growing stronger, and stronger and stronger, for the day that he could fight and beat Ace. That day will never come, now. Luffy could not even protect his crew—then again, perhaps it is for the best that they got split up. Had they been together, he would have wanted to storm Impel Down and head on to Marineford anyway. Perhaps his comrades would have made the process move quicker, and they never would have even had to go to Marineford. On the other hand, when Luffy thinks of foes like Blackbeard and Magellan, he knows that he would not have been able to protect them all; he would have lost one or more comrades to save Ace, and maybe even then he would have lost Ace too.
Luffy thinks the world seems bleak and empty now, without his brothers. He remembers how Ace converted his grief at Sabo's death to anger, and pushed on. Luffy can't do that, because he knows only too well that even if he fights Akainu and wins, Ace is never coming back. So the grief takes over.
Ace and Sabo called him weak. At first with disgust, and later with affection. They helped him grow stronger, and he knows full well that he has them to thank for the fact that he has been able to protect his comrades this far.
But everything comes back to the fact that they are gone. Gone forevermore, and Luffy is left alone.
Luffy thinks about finding his comrades, briefly. But he cannot bear the thought. He doesn't want to see any of them again, because he will want to protect them again even though the world has shown him only too well that he cannot and never will. Any protection Luffy can provide is only temporary, to be overthrown by the first real foe they encounter.
In principle, Luffy does not like it when people want to die. He himself has fought too far for too long in a world where it would have been only too easy to give up and die. Luffy doesn't object to people wanting to die, unless they do so out of some twisted sense of duty—like Sanji had, somehow thinking that dying would be a suitable repayment for Zeff saving his life. Still, Luffy himself has lived through everything, and has always known that if nothing else, he must live.
Except that now, Luffy wants to die. Really and truly, he wants to lay himself upon the moss on the ground, close his eyes, and never wake again. He doesn't want to be Pirate King—no, he still wants that more than anything—but he can't. Luffy is weak. Luffy is helpless.
Luffy remembers crying the first time he killed something to eat it. Luffy remembers Ace and Sabo looking at him incredulously when he refused to harm anything that was neither food nor an immediate threat. He sees, now, that he was looking at the world with a soft eye. For Luffy has always talked of putting his own life on the line, and that of his comrades—them, Luffy has always known, he can protect. But the world did not take Luffy's life—not even any of his comrades' lives, as far as he knows.
Instead, the world merely separated Luffy from his comrades, then took away the life of his brother.
Now, Luffy understands. Dreams don't come true. The world can and will tear families apart like wet paper, and relish the families' despair. Life is brittle, and can be lost at the drop of a hat—and this is another pastime that the world enjoys.
Closed or open, his eyes only see Ace's melting body. He can't stop feeling the heat of Ace's body against him, warmer than flame and a stark contrast with the comparatively cool air against his back. The only smell that reaches Luffy's nose is the stench of burning. He can detect flames and magma, and burning flesh within that smell. He wishes he could cry. He knows that tears are running down his face, but there should be more—they should be flooding this island, and the whole world. He screams at the top of his lungs, but he is too quiet.
There is nothing that Luffy wants to do anymore. What is the point in being Pirate King in a world he hates? Why is he even alive, when the two best people in the world are not?
He closes his eyes. He opens them. He covers his ears, and uncovers them. He tries not to breathe, but he only passes out and wakes to find himself breathing again, and still smelling the stench of burning. He scratches at his skin through the bandages, but he still feels Ace's hardened body in his arms.
Nothing is true anymore. Luffy doesn't know or want anything anymore.
For the first time in his life, everything that matters is gone.