Disclaimer: I don't own One Piece.
1.
The first time that Sengoku hears the name Ace is when Garp returns from four months of hiding and dodging the Marine bases from Baterilla in South Blue, across the Grand Line, and to Dawn Island in East Blue.
He comes back with a picture of a baby swaddled in his arms and tears in his eyes for his cute new grandson. Garp shoves the picture into his face and praises his grandson loudly as they sit in Sengoku's office, their promotions just coming in from their capture and execution of Gol D Roger.
"Looks too much like his father," Garp sighs at one point, cracker crumbs down the front of his uniform and his nose wrinkled. "His mother was prettier."
"I'm surprised that Dragon had a child. He seems content to try and take over the world." Sengoku returns buried in paperwork, his head ducked.
"He's not Dragon's." Garp says pulling a face. "Portgas D Ace, Sengoku."
Sengoku pauses, pen tight in his hand, "Garp."
"He's a baby, Sen."
"Who gave you a baby, Garp? There's only one Portgas that I know and I thought you reported her dead on Baterilla."
Sengoku isn't stupid. He knows as well as Garp that the Oro Jackson spent more time than it needed to liaising with a woman who worked for Dragon. A woman who was named Portgas D Rouge. Who had died almost five months ago, right around the time that Garp had made his final report and then vanished into the Grand Line.
"Rouge died, her son," Garp shrugs. "He's not going to be like his father."
"Because you weren't content hiding his son by yourself, you have to drag me into this?" Sengoku hisses.
Garp stares at him for a long moment, "He's a baby, Sengoku. He's not even five months old and he deserves to live no matter his father's crimes. And his name is Portgas D Ace."
"At least you gave him his mother's name." Sengoku sighs.
.
2.
"Brat made a friend," Garp states as he throws himself onto Sengoku's couch. "They think they're being sneaky but Dadan's pretty sure that they're stealing money for their 'Pirate' fund."
Sengoku sighs, "Garp, I know I have told you this previously, I want nothing to do with your highly illegal actions. One of us is going to get their careers ruined when this comes to light, I would like not to make it two."
Garp ignores him, Garp tends to ignore anything that he doesn't like.
"Brat and the other Brat think they're so tough, ha! I showed them, took them both under my wing while I was home, showed them how to be proper Marines." Garp carries on.
Sengoku says nothing, if he's careful then he can claim that Garp drops on his couch and rambles and to be honest he's not sure what the man is talking about half of the time when this comes back to bite them both in the ass.
"Did some research on the other Brat too. Can't be too careful," Garp explains and Sengoku has no idea what is being said. "A Noble. Outlook's son and heir. Seems he thinks that they're greedy and corrupt. Wants to find out the truth of everything."
"Portgas charmed a Noble?"
"Ha! I knew you were paying attention!" Garp shouts. "And no. I think the other Brat befriended the Brat. Brat's not the friendliest boy, likes to beat up people in Gray Terminal when they insult his father."
Sengoku pinches the bridge of his nose, "He knows who his father is?"
"Every kid should know who their father is." Garp shoots back. "Did I tell you I'm a grandfather again?"
"Oh?"
"Dragon sent one of his men to tell me," He scrambles through his suit pockets and pulls out two pictures. "That one's Monkey D Luffy."
It's a little boy with the same face that Sengoku remembers from the pictures of a young Dragon, though there's a bit of a difference, he thinks. The second is the one that he dreads.
The blond child with a top hat and a cravat looks ready to bolt off frame, a metal pipe held in hand like a weapon. Roger's son glares much like his father did, silver eyes narrowed and arms crossed over his chest.
Sengoku is starting to fear that he might get in as much trouble as Garp when this comes out.
.
3.
"That No-good grandson stealing bastard!" Garp declares slamming the door to Sengoku's office open.
"Welcome back Garp, do you know that you went missing for two months with no explanation? Where did you go?" Sengoku asks coolly. "Please tell me that you didn't ditch your responsibility to go play with your grandsons."
"Course I didn't," Garp sounds offended, "Shanks was hanging around Dawn."
Sengoku breaks the pen in his grasp and sighs, he had liked that one too, he wipes his hand on a napkin and pulls a new pen from the drawer full of them. He taps it against his paperwork for a long moment before looking up at Garp.
"He knows of the child?"
"Nah. Least not the one you think. He befriend my Brat." Sengoku frowns and tries to remember which Brat that was. "My Brat ate a Devil's Fruit, I was going to start them on water training next vacation and now it's ruined because that grandson stealer stole my Brat's ability to swim."
"Is that Portgas, the Noble, or Dragon's son?"
Garp looks disappointed, before sighing, "My Brat is Luffy. Other Brat is Sabo. Brat is Ace. My Brat can't swim anymore, how is he suppose to become a strong Marine!"
"Garp, we do have a number of Marines who can't swim, including several whom look to be heading towards Vice-Admiral in the next decade or so." Sengoku says calmly.
"Oh, right." Garp laughs. "I forgot. Can still start the other two Brats on it. My Brat can keep fighting with the monkeys I suppose."
Sengoku closes his eyes and counts to ten, he doesn't want to know what monkeys have to do with training children to be Marines. He doesn't want to know how Garp is training this children. It's none of his concern.
"Anyway, the Brat's gotten taller and other Brat's started teaching both of the other brats how to read and write. The Brat's even more violent than last time I stopped by. My Brat seems to like them well enough." Garp continues.
"Garp. You have to call them something else, I can't keep three only barely different versions of Brat straight."
Garp laughs, dragging out more pictures, like he does every time he comes back from visiting Dawn, "No."
Dragon's brat has a new wound underneath one of his eyes, still pink and raw at the edges, and a rather familiar straw hat hanging from his neck. The Noble has lost a tooth somewhere along the line and gained a tailcoat.
The last one is the Roger's. A taller than last time Sengoku saw a picture and face somehow less surly than he was expecting. The look reminds Sengoku of Portgas more than Roger.
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4.
"That BASTARD!"
Sengoku sighs, already knowing that the pounding footsteps are headed his way. He leans back in his chair just in time as Garp busts into his office thrusting a wanted poster into his face.
"I trained him to be a strong Marine and look what that Bastard Brat did!"
The picture is slightly blurry, Sengoku frowns, they'll have to have another taken soon, but it's obviously the oldest of Garp's brats. Portgas D Ace written in simple font underneath the picture with a short list of details that make it onto every wanted poster.
"I see his son followed in his footsteps." Sengoku says unsurprised. "As I said that he would the first time you burst into my office to talk of your grandson."
Garp frowns, "My Brat says that he plans on trying to take down Whitebeard. Maybe, if he's good enough, we should consider making him a War Lord."
"It would be the only thing that saves his life, should someone learn of his parents." Sengoku agrees lightly, head tipped to the side. "What is on the Brat's head?"
"Ah, my Brat gave him a hat. Something about how he and the other Brat both had them and how the Brat needed one too." Garp shrugs. "At least his bounty isn't bad."
"That isn't something to be proud of!"
"If he's going to be a pirate at least he's not going about it poorly!"
Sengoku wonders if Garp thinks the same of his own son and dismisses the thought. It's bad enough that he's gotten attached to the Portgas mess, he doesn't have time to deal with more.
.
5.
It's another wanted poster.
Sengoku sighs but lifts his head and blinks twice, "Didn't you say?"
"He joined Whitebeard's flock," Garp grumbles. "The stupid Brat. Had the nerve to join Whitebeard. I raised him to be a Marine!"
"At least he didn't join Dragon like his mother?"
Garp frowns, "I think it would have been better if he had. Dragon's people don't have half as many bounties as a pirate would. Hell, last I heard his damned second in command didn't even have one."
.
+1.
Sengoku stares down at Whitebeard's symbol tattooed large enough to take up Portgas D Ace's entire back, unable to bring himself to look down to where Garp has taken up his stance. Garp who is about to watch his grandson be executed before him by the laws that he protected. Garp who spent the first three days of Portgas' capture hiding out on Level Six crying his eyes out.
"I have something to tell you all. Portgas D Ace, it's about the significance of his death today. Ace, tell them the name of your father."Sengoku can hear Garp laugh at something Tsuru says.
"My father is Whitebeard."
Sengoku wants to sigh, just as stubborn as Garp, "No."
"Yes he is! Whitebeard is my only father!" Portgas shouts back.
"We looked for you with our eyes wide open at that time, because we heard there might a child of that man on some island. Based on a small amount of reliable information from Cipher Pol, we checked all newborns, and pre-born children, and their mothers and we couldn't find you." Sengoku clenches a fist. "No wonder. Your mother risked her life to bear you. She used a trick that can be called Mother's Pride. That has mislead us...Indeed the whole world."
Portgas doesn't flinch.
"There is an island called Baterilla in South Blue. Your mother's name is Portgas D Rouge. She did something that completely defied natural law for the love of her child. She kept her baby inside her womb for twenty months."
Sengoku can hear the noise that Portgas makes this time. Can hear it over the confusion from the crowd below and the whispers starting up.
"And so she could give birth to you, she lost all of her strength and passed away right there. A year and three months after the father's death, the child was born with the blood of the world's most heinous man in his veins. That was you. You know it, surely?"
"Your father is the King of the pirates, Gold Roger."
Garp would never forgive him.