Monkey D Garp has been in the marines for the vast majority of his life.
He's fought and bled and killed for them, and throughout it all told himself that it's for the greater good.
He tells himself that he can change it from the inside, that he can do more good for the world from a position of power. He tells himself that he can raise good soldiers, like Coby and Helmeppo and Smoker. He can raise compassionate soldiers who will inherit this bloody organization after he and the rest of the old guard are gone, and they can turn it into something better, something more like the shining image they present to the rest of the world.
So he turns a blind eye to the buster calls and the torture of the Impel Down prisoners and the slavery of the fish-men and giants and mink and humans.
He turns a blind eye to Ohara, even though the eyes of the devil child stare out from her wanted poster and burn themselves into his mind.
Then Luffy, the brightest light in his life, declares war on the World Government for her, and through his gnawing terror, he feels a burning shame, that Luffy had so easily achieved what Garp himself had been too scared to do.
Then Ace, as much a grandson to him as Luffy, is thrown into level 6 of Impel Down, with Crocodile and Shiryu and Catarina Devon. Not for trying to overthrow a nation. Not for murdering hundreds of prisoners in cold blood. Not even for any of the crimes he had committed under the name of the Spade or Whitebeard pirates. Ace is thrown into Impel Down for the simple crime of being born.
Then Luffy, who looks up to that brother of his more than anyone else in the world, punches a Celestial Dragon at Sabaody, and Garp laughs and doesn't hide his pride, not for one second. He knows, without even a hint of doubt, that Luffy won't sit back and let his brother be killed without a fight.
And suddenly, he finds he can no longer turn a blind eye.
Because Garp has spent his entire life giving and giving and giving for the marines. He's broken off parts of himself, turned himself into a monster, let himself be called a hero even though he knows the kinds of men he takes orders from.
But his grandsons? The boys who've taught him love and happiness and acceptance? The boys who still call him "grandpa" and smile at him even though it's his job to hunt them down and kill them?
He wouldn't give them up for anyone.
And maybe it makes him a terrible person, that he can put up with all the other horrific things the Marines have done for the greater good.
Maybe it makes him a terrible person that he only breaks when his family is on the line.
Garp finds he can't bring himself to care.
It's just another bullet point on the long list of sins he's committed in his life.
He's already become a monster for the government.
This time, he'll be a monster for his grandson.
Ace's grandfather loves him.
It's one of the cardinal truths in his life, something he's never once doubted, even in his darkest moments.
But his grandfather is also a fundamentally good man.
He's a good man who fights to save the world with every breath he takes. He's a man who never does anything selfish like putting the well-being of his family above the greater good, no matter how much Ace knows he wants to.
He's a good man, and Ace loves him, dammit, so when Garp shows up in front of his cell, stone-faced, and announces that Ace's execution has been moved up, Ace doesn't break down sobbing.
Ace doesn't beg for his life or ask why his own grandfather is leading him to his death at the tender age of twenty.
Because Garp is a good man.
Because Garp loves Ace.
Because Ace doesn't want to cause his grandfather any more pain than he already has.
So Ace stands up on creaking legs, says farewell to Jinbei, and follows his grandfather out of Impel Down, flanked on all sides by grim-faced guards whose job it is to make sure he doesn't try and make a break for it.
Ace steps onto his grandfather's warship to the sound of the Impel Down guards' thunderous farewells, and is confused, for a second, when he sees only about a dozen people on deck.
They're a motley assortment.
Their movements are practiced, perfect, but they wear their uniforms like costumes that don't fit quite right. As if it's all new to them.
His grandfather's ever faithful shadow, Bogard, is the one to receive Ace as he steps on board, flanked on either side by two young new recruits, both stiff with fear. The pink-haired one, who couldn't be much older than Luffy, smiles nervously at Ace.
Garp laughs and laughs, waving goodbye to the guards of Impel Down, basking in the adoration directed at the hero of the navy.
Then, he turns his back, and the smile slides off his face to be replaced with an expression of such pure, unfiltered loathing that Ace can't help but stumble back.
(It's not directed at him.
Ace's grandfather loves him.)
Garp starts calling orders to his men, ordering them to set sail while he escorts Fire Fist Ace to his cell.
"Aye sir!" comes the resounding answer from the people gathered on deck.
The two young recruits run off to take care of their duties, and now it's just Ace and Garp.
He follows his grandfather below deck, mind still swimming with confusion at how...odd everything about this whole debacle is.
There's an idea forming at the back of his mind, though.
A terrible idea about betrayal and rescue and a man who loves his grandson enough to be selfish for once in his life.
He pushes the thought down deep, where it can't hurt him with how much it makes him want.
It's not possible, and he's not about the break his own heart aching for things that he knows won't happen. He refuses to let anyone have the satisfaction.
But the room he's led to isn't a cell.
It's a bedroom, with a comfortable bed and a desk in the corner with a lamp on it and a wardrobe along one wall.
Ace takes a couple of steps into the room, looking around in confusion before turning to send his grandfather a questioning gaze.
Garp stands at the entrance to the room, watching him with eyes bright with tears.
His hand is clenched in a fist at his side, and Ace has a moment to wonder if he's about to get a fist of love.
But instead, Garp takes a few, halting steps forward, and takes Ace's manacled wrists in his own with a tenderness Ace wouldn't have thought possible from him.
A few seconds later, the seastone cuffs land on the floor with a thud and Ace stares at them, uncomprehending, for such a very long time.
Ace's grandfather loves him.
That was never in question.
But he's also a fundamentally good man, who would never do something like putting the well-being of his family above the greater good.
(What Ace seems to have forgotten is that theirs is a family of selfish people, who never learned how to let go of the things they want, and Luffy had to have gotten his pig-headedness from somewhere).
Standing here, in front of this man who had betrayed his entire way of life, thrown away everything he'd worked towards for half a century, all for his sake, Ace finally lets himself fall apart.
A sob tears out of his chest, ugly and painful and devastating.
He steps forward to throw his arms around his grandfather, and feels that familiar embrace wrap him up in its safety.
And maybe Garp is sobbing, body shaking and hot tears leaving trails down his cheeks, but suddenly Ace is seven again and the whole world wants him dead and maybe it would have been better if he had never been born. But he's in the safety of his grandpa's arms, where nothing in the world can ever hurt him again.
Because Ace's grandfather loves him.