A/N: My answer to the question: How would Marine!Luffy react to Ace's execution? Also my second go at writing in present tense.
The light of the setting sun sneaks through the window curtains and falls on the stacks of paper sitting on Sengoku's desk. Sengoku has one hand on his forehead, slightly massaging his temple in an attempt to free himself of a headache.
The cause of this headache is sitting across from him, munching on rice crackers and getting crumbs everywhere. Garp finishes the rice cracker he's holding and goes to reach for another one, but he stops when he sees Sengoku's glare.
He swallows the last bit of chewed up cracker in his mouth and asks, "Anything else today, or do you just want me to get out?"
Sengoku sighs. "There is something. You've heard we have a new prisoner in Impel Down, haven't you?"
Garp sobers at this. "I have," he answers. "I've been to visit him already."
"And your grandson, Luffy…" Sengoku sees Garp tense when he says this, and he knows he won't be getting good news. "How has he reacted?"
"I haven't told him yet," Garp admits, averting his eyes from Sengoku's. "He doesn't know."
"He needs to know soon, Garp. The boy makes an exemplary Marine, but you can't help him succeed by hiding him from turmoil." Sengoku's eyes narrow. "Unless you think he'll choose him over us?"
"Of course not; my boy's loyal," Garp says, "but… he can be unpredictable, too."
Sengoku scoffs. "I've noticed, believe me."
"I would have told him right away," Garp insists, "but I just don't know how it'll affect him."
"Inform him of the situation immediately."
Garp nods and stands to leave, but then Sengoku says, "One last thing," and he pauses.
Sengoku opens a drawer on his desk. He rummages through the contents for a second before he pulls out what he was looking for and tosses it to Garp.
Garp looks down at the object in his hand. "What's this for, Sengoku?"
"You'll know when the time comes," he says. "Call it… a test of character."
Garp finds Luffy exactly where he expects to — in the Headquarters' cafeteria. Despite the boy's messy eating habits, his crisp white uniform remains unblemished and that causes a gleam of pride within Garp's eye. He tries his best to conceal it, but Luffy catches it when he looks up at his grandfather and grins.
"Yo, Grandpa!" he greets cheerfully, and then shoves an entire steak into his mouth whole. His very being is buzzing with happiness and Garp feels horrible about what he's there to do.
"Hello, Luffy." He allows himself to grin; that boy can brighten anyone's day, even if he doses them with guilt at the same time. "Having a good day?"
"Yeah! I beat up some pirates, and I got another letter from Coby, and the cafeteria serves lots of meat of Thursdays!" He gestures to his meal.
Garp's grin lessens until it drops. "I really hate to ruin your good mood, but I'm afraid I'm on orders."
Luffy's smile leaves as well and is replaced by a curious stare. "What's wrong?"
"…Come with me, Luffy. There's something you have to see."
Garp takes Luffy all the way to Impel Down. The guards are annoyed that they had to drop in unannounced but let them through anyway.
Luffy surveys the prison levelly as they descend, paying no mind to the incarcerated criminals insulting them left and right all the while. Garp knows he's never been inside before, but he has always had questions about the place — including some very strange ones Garp has never had any idea how to answer.
They arrive at Level Six and Luffy suppresses his intrigue, even though they are on a top-secret floor that not even they had previously known existed, because he knows that this is a serious occasion.
Garp leads his grandson to the cell where the new prisoner is kept and, while Luffy processes what he's being shown, steels himself for whatever reaction might come.
"…Ace?" Luffy whispers. A light clang of chains comes from the cell as Ace lifts his head in acknowledgement. "What— Why are you-?"
"He was captured recently," Garp tells him solemnly. "I didn't tell you sooner because, well…"
Luffy ignores him. "Ace," he calls, "Ace, are you hurt?"
Ace only scowls and Luffy winces.
"I know you don't really like me," his voice wavers slightly, "but you can talk to me at least, can't you?"
Ace looks away and deliberates. "…Fine," he bites eventually.
"Are you hurt?"
Luffy's sure that's a lie — he can smell the blood coating him from where he is — but he doesn't dare push. He knows Ace's temper well.
"How did you get here? Are they feeding you? Where's Sabo?"
"Sabo's with our crew," Ace says irritably. His pride does not permit him to answer the other questions.
"How can you be here?" Luffy asks again. He doesn't catch on this time; he's always been a bit oblivious. "Have you been fed?"
"Will you just leave me alone?" Ace snaps. "I don't want to speak to you, you goddamn Marine!" the last word came out like an insult.
There's a short pause that seems to drag on forever. Garp glances between his eldest and youngest grandson apprehensively.
"…Alright," Luffy says finally. "I'll go. But I'll come back."
Ace closes his glaring eyes and turns his head away from the younger boy. "You shouldn't bother."
Luffy does, indeed, bother. In fact, he goes to a lot of trouble to prepare for his next visit to Ace. He manages to talk the warden into letting him inside the cell, and even though they find it on him when they search his person, he's allowed to bring a small parcel of food into the prison under the assumption that it's his own snack — he is, after all, well known for his appetite.
He gets to Level Six and meets Ace's scowl with a smile, which turns into a grin when he sees Ace's shock as he walks right through the cell door.
"Hi, Ace!" He walks up and stands right in front of Ace. The prisoner looks as if he wants to hit him, but the chains keep him from moving his arms. "I brought you food," he whispers conspiratorially, taking out the parcel and unwrapping it.
Ace's scowl deepens. "I don't need charity."
"It isn't charity, it's kindness." Ace opens his mouth to protest, and Luffy takes advantage of this to stick a meatball between his lips. "Good, ne?"
Ace narrows his eyes, but chews and swallows the morsel anyway. "Why be kind to me? I'm just trash in your eyes, aren't I?"
Luffy frowns. "No, you're not. Don't put me in the same boat as people like Sakazuki."
"Yes I am! Marines like you are supposed to hate pirates like me," Ace says. If he could only make some kind of frustrated gesture, he would. "Especially me! I'm nothing but scum to you!"
"We never did get along well," Luffy admits, "but that doesn't mean I don't care about you."
Ace makes a noise that he might have meant as a scoff, but sounds a bit like a sob. "I'm a pirate, you're a Marine! How could you possibly care about me?"
Luffy looks up at his face, which was contorted in confusion and anger, and directly into his eyes with a burning sort of resignation. "Sometimes… I don't really know."
Ace's head drops in defeat. "You're such a pain," he complains, but he lets Luffy finish feeding him without a fuss.
When the food is gone, Luffy wipes the crumbs, along with a bit of blood, off his face with a handkerchief and walks away in silence. Ace watches him go until he disappears.
He sighs to himself. "…I don't understand you at all…"
Luffy isn't watching where he's going; he's watching the builders as they put the finishing touches on the execution platform's structure.
It's meant to be today. Ace is meant to die today.
It's early, early morning and few people are awake now, but he and Smoker are both alert enough to be assigned to patrol the area together. Smoker keeps shooting him concerned glances when he thinks he isn't looking, and Luffy can guess why.
A pair of builders, carrying a long wooden plank towards the platform, are knocked to the ground with a crash. Luffy and Smoker pivot to face the sound and see Garp barrelling in their direction recklessly.
"Luffy!" The old man yells.
The boy steps forward. "Grandpa, what happened?"
Garp comes to a stop in front of them and schools his distressed expression. "Nothing, nothing… But I need to talk to you."
They leave Smoker to patrol by himself, and Garp brings Luffy into a private room and locks the door.
"I need you to keep something for me," Garp says once the door is secured. He reaches into his pocket and pulls out the object Sengoku had given him on that day in his office, then hands it to Luffy.
Luffy, for his part, is much quicker to deduce what it is than his grandfather had been. "This is…!"
Garp hushes him. "Hold onto this for today. I can't trust myself with it."
Luffy's grip tightens around the object and he looks suspiciously at his grandfather. "Why do you have this?" he demands.
"I was given it as a test of character," Garp says quietly, "a test I think I failed."
At the actual execution, Luffy and Garp stand on the platform with Sengoku. Luffy nearly loses his lunch when he sees Ace kneeling there in chains.
If he does nothing, Ace will die.
If he tries anything, he'll be a traitor.
Ace doesn't even like you, something inside him hisses, and the Marines are your people, your life, your home.
Sengoku is talking, and Luffy feels like he should be doing something.
What's the point? Why even try? Ace said it himself, "You shouldn't bother."
Ace will die.
He hates the thought yet it's the only one that makes sense. Ace will die today, he thinks to himself, and it hurts him. He doesn't want Ace to die, but he can't betray the Marines.
And then something astonishing happens, even though the Marines were expecting it completely. Whitebeard's crew bursts in with their ship, and the very first person Luffy sees, the first person off the ship and onto the battlefield, is Sabo.
He flinches as he watches Sabo charge forward, tearing down Luffy's colleagues and friends as he goes. The rest of Ace's crew joins the fray and more and more people die, and it's painful for Luffy to watch, but he thinks that maybe, just maybe, they can save Ace on their own, and it comes as a huge relief.
Ace starts hurling insults at his own crew, and Luffy thinks it's almost comical now that it isn't so stressful anymore.
Garp jumps down off the platform and starts fighting off as many pirates as he can, making Luffy realise very suddenly that he doesn't know which side to fight for.
He can't very well fight Ace's friends, can he? What on Earth would he do if he has to fight Sabo? He just can't do it. But he can't fight the Marines, either.
He turns to Sengoku for direction and the man just signals for him to stay where he is, which is alleviating enough. But the object in his pocket is burning him, nagging at him, and now he knows why his grandfather couldn't bear to hold on to it.
The executioners draw their blades, ready to sever Ace's head, and Luffy panics.
Combatants on the battlefield start to fall, Marines and pirates alike. The executioners faint as well, and Luffy realises he accidentally let his Haki slip into his yell.
But it doesn't really matter right now. All that matters now is that the people left standing are too busy staring at him in shock to get in his way.
He goes to Ace swiftly and drops to his knees. It takes him no time at all to take the key his grandfather gave him from his pocket and use it to open Ace's cuffs.
He'll be a traitor.
Sengoku is starting to recover himself, but Ace, meanwhile, is too stunned to do much but gape at Luffy. It's a long drop down, but Sengoku is furious, so without another second to spare Luffy shoves Ace over the side and lets him fall. He's nimble. He'll be fine.
Luffy doesn't jump down to join him because Sengoku has grabbed his collar and pulled him back.
Sengoku starts speaking again, this time about Luffy instead of Ace, and the event is still being broadcasted so Luffy knows the world is going to hear.
"You had potential. You could have been my successor some day, but you've lost your chance," the man says with some disappointment, a lot of anger, and a hint of sadness. "I thought we could make a good Marine out of you, but I suppose that was more than could be expected from the son of the Revolutionary Dragon!"
Sabo's trying his hardest to get Ace back to the ship, but his brother isn't making it easy. He keeps trying to dig in his heels and look back over his shoulder.
"Come on, Ace!" he insists. "We have the chance to escape, we've got to take it!"
Sabo grabs his wrist and pulls as hard as he can, but he's exhausted from the battle and Ace is sturdy, so it only gains him a few more steps. Ace is still trying to look at Luffy.
He really, really doesn't understand. After all he and Sabo used to do to that boy, like shun him, and bully him, and hit him, how on Earth can he still care about them? They did all that only because he said he wanted to be a Marine when they wanted to be pirates. How can he even like them after they were so stupid?
And still he worries about them. Ace can see him now, at the top of the platform while Sengoku tells the entire world things about him that were meant to be secret, and the only thing the boy does is watch over their escape. He doesn't even care about what happens to himself. How can anyone be so selfless?
All his guilt for what he's done to Luffy grips him and makes a thick, cold lump in his stomach when he catches Luffy's eye. As soon as Luffy sees him looking, he disregards Sengoku, who is now picking up one of the executioner's blades, to grin at Ace.
Ace feels worse at that grin than anything else. That grin is directed at him and him only, and is filled with nothing but joy and relief and pride. It remains in place even as Sengoku plunges the blade through Luffy's chest.
The blade is retched out and Luffy begins to bleed heavily. Sabo is trying to pull Ace back to the ship and the crewmembers that fainted at Luffy's yell are either being carried back or shaken awake by their friends. Ace goes with Sabo more willingly now but keeps his eyes on Luffy, who's bleeding out, yet no matter what happens Luffy's goddamn grin never fucking leaves.
They escape in their ship, leaving Luffy behind, dead on the platform, and Ace retreats to the bathroom where he vomits out of guilt. It occurs to him that the food Luffy brought to him in the prison every day is probably what he's losing into the toilet now, and that makes him feel even guiltier. For days and weeks and months he sees that grin every time he closes his eyes.
He doesn't understand that boy at all.
A/N: Why do I feel the need to torture the D brothers in my stories? Between this, Inversion, and Player One, I don't know how much more I can get away with before their fangirls come at me with pitchforks and torches.