Disclaimer: RWBY and One Piece are the property of their respective owners and I do not make any profit by writing this story.

Now that the legal stuff is done, let's talk business. This story has been a request from a friend of mine here on FF, who is currently unable to write and wants some new story ideas on this site. So I did her the favor and well... see for yourself.

The basic setup for the story is very simple. Remnant is an Archipelago in the South Blue, so it's all part of the greater One Piece world. The events that lead to the four main characters of RWBY meeting are quite different this time, which will be explained in due time. Whereas RWBY sets out to the sea as a pirate seeking adventure and fighting the corrupt World Government, Yang ended up with the Marines...

Telling anything else would spoil too much, so I shut up now. Have fun with the first, short chapter.

In his many years as a Marine, Vice-Admiral Monkey D. Garp had seen a lot. Not all there is to see, but enough that he felt confident enough to say that nothing could surprise him at this point in his life. Oh, how wrong he was with that assumption.

At that very moment, the so-called Hero of the Marines stared at the bundle in his arms with wide eyes, his mind blank and posture rigid. He was completely at loss, not knowing what to do or what to think.

The woman before him, who had given him the bundle watched with a look of utter annoyance, as she waited for him to react to what she had told him before. But the reaction seemed delayed, for obvious reasons.

"What... why?"

"Pah," the woman spat, "Why am I the one getting punished with a family of idiots? It's a baby, old fool."

"I can see that, Raven. Whose baby is this? What have you done now?" Garp demanded, his eyes fixed on the sleeping babe in his arms.

Such a tiny little human being. So innocent and pure. He was afraid that he would crush the child, with all his unrestrained strength. He wasn't used to handling things with care...

"That's my daughter. Your granddaughter. I've named her Yang," Raven told him.

She kept her distance from him and the child. The moment she had placed the child in his arms was the first time she had actually touched him in more than a decade. Even now she seemed to fear that he would either lash out again or worse, latch onto her and force her to stay. As if he could do such a thing with a baby in his arms.

"Granddaughter..." Garp muttered.

He watched the sleeping girl with a new kind of fascination. His granddaughter... his daughter's daughter... Somewhere along those last thoughts, his brain short-circuited and his eyes found Raven once more.

She had taken some more steps away from him. Getting further out of reach. For a good reason. Estranged or not, the idea that someone had touched his daughter still made him angry. Garp was well aware that Raven would not tolerate his interference in her life. She had made that clear when she had run away as a child, never to be found unless she wants to be found.

"Try not to break her. I know you are only good at breaking things, but at least try to keep one family member whole," Raven growled.

"Don't you dare to blame me for your own decisions!" Garp bellowed back, ignorant of the fact that he had a sleeping child in his arms. Said child did not like the sudden commotion and began wailing loudly. "Oh, no, no, no. Don't cry, Yang. Grandpa Garp is not going to let anything or anyone hurt you. Nothing bad is here, nothing bad." He tried to sooth the baby and began bouncing her up and down. She didn't like that either and wailed even louder than before.

"Damn old man, can't you do anything right? No wonder my brothers and I are so messed up," Raven barked at him. "Stop manhandling her like you would one of your subordinates. She is a baby, not pineapple."

"I..." Garp was at loss. "What am I supposed to do with your daughter?"

Just why was Raven here with her child? She had not tried to contact him since the day her mother had died, the day she had set sail to the other end of the world to be away from him. Garp had a feeling that this wasn't really a social call. No, this wasn't an attempt to reconnect... but that could mean that...

"She's your problem now. Do with her as you please," Raven shot back, "I neither have the time nor the patience for her."

"You would abandon your own daughter?" Garp exclaimed, feeling aghast by his daughter's cold-hearted plan. He wasn't exactly father of the year material either, but he had never willingly left any of his kids alone. They all left him at one point in time, but it was never him to walk away first.

"I'm leaving her with you. Try your best this time, you have already failed thrice, maybe four is your lucky number," Raven said, as she turned away from her father and began to walk away.

"And what will you do?" Garp demanded to know.

Raven stopped for a moment but didn't look back as she answered, "What I always do. I'm a pirate after all."

Garp began to hurry after her, intent to stop her from fleeing again. Now he still had a chance to keep her with him, to make things right again. With her daughter, he might even be able to convince Sengoku to help him. Together they would find a way to remove Raven from the Marine's shit list. But should she abandon her child and walk away, not even he would be able to change her fate.

But Raven had never been one to be caught. Not by him, not by anyone else. A great many Marines and other pirates had tried. None had succeeded. Even now she quickly disappeared, leaving her father alone with his infant grandchild.

Yang continued to wail the entire time, as Garp just stood there, in the middle of nowhere. This was definitely not what he had expected to happen when he woke up this morning. He had expected trouble yes. What else was he supposed to expect, after finding a message pinned to the door of his cabin with the very dagger he had given his daughter for self-defense when she had been a child? But this... he suddenly felt so much older, just by knowing that he was a grandfather now.

Garp sigh worriedly. A baby... what was he supposed to do with a baby? Maybe leave her Dadan and her bandits. Surely little Ace would appreciate a companion while growing up... But somehow the idea of a girl being left in the care of bandits did not sit entirely right with him. Maybe there would be someone in the nearby village instead? She could go and visit Ace once she is a bit older and he could train them together. He would make some fine Marines out of them.

"What the hell am I going to do with you?" he wondered loudly, as he looked at Yang.

The little girl had settled down again, her previous agitation completely forgotten now. Instead, the girl looked at him wide-eyed. Lilac eyes... she must have gotten her coloring from her father. But the face was all Raven... well at least compared to what he remembered of his daughter's earliest days.

"Hm... let's get you back to my ship for now. You must be hungry, I sure am," Garp mumbled. But it was then that he realized that he had no idea what babies eat. A battleship was surely not equipped with what a baby would need... Oh well, he would let Bogard deal with that problem. His right-hand-man had always been good at dealing with Garp related problems.

As the Vice-Admiral arrived back on his ship, his men watched their commander with great curiosity. While it wasn't uncommon for Garp to leave for days at a time, they had rarely seen him jump off the ship in such a hurry before.

And now he was back, but he wasn't alone. Every Marine on the ship was used to the admiral's antics by now, but when Garp the Fist returns from a seemingly abandoned island with a baby in his arms, even the most disinterested Marine starts asking questions.

The Vice-Admiral's right-hand-man, Captain Bogard, was the only one who dared to voice his question, though.

"Sir... where did you find that baby?" the captain asked.

Garp looked at Bogard than at his granddaughter, before a huge grin spread on his face.

"This, Bogard, is my granddaughter."

"Granddaughter, sir? A grandchild like... the other one?" Bogard dared not say Ace's name. He was one of the few who knew about the boy, who knew that Garp kept a child hidden that the Marines and the World Government would kill in a heartbeat for the evil deeds of the child's father.

"No, Bogard, this is my own flesh and blood. My little Yang!" Garp announced proudly.

The other Marines on deck started muttering among themselves, shocked to hear that their monstrous admiral apparently had a child and now a grandchild to follow in his footsteps. All those who had been on the receiving end of Garp's temper shuddered in fear.

"Go and see if we have anything for Yang to eat, Bogard. And set sail for an island with a big enough city. We need to get supplies for Yang!"

"As you say, sir," Bogard replied, "But there is one matter that requires your attention first."

"No, Bogard, my granddaughter is the most important..." he stopped when he felt something pull at the pants of his suit. "Oh no." When he looked down, he saw a small white goat trying to chew on the leg of his pants, oblivious to who was currently wearing said pants.

But it wasn't the goat that bothered Garp the most. It was his own lack of attention. As he looked towards the other side of the ship, he saw that he was no longer alone. Next, to his own, there was a small fleet of other Marine vessels. And he knew exactly under whose command those ships sail...

"Garp! It's about time that you get back, we have important things to discuss!"

A man came out of a nearby door and stepped onto the deck of Garp's ship. Dressed immaculately, with his Justice Coat hanging limply over his shoulders, Admiral Sengoku came into view.

Garp mumbled some curses as he saw the man. Usually, he would welcome a chat with his old friend. Rile him up a bit and all that. But this had to be the worst timing ever. Garp really didn't want the higher-ups in the Marines to know about his granddaughter just yet.

The lower ranking Marines, who had been eavesdropping the entire time began to scramble, busy to get away from the Admiral as quickly as they could. Some nearly fell off the ship, as they attempted to look as busy as possible.

"What is the meaning of this, Garp?" Sengoku bellowed as he saw the child in friend's arms.

"This is a baby," Garp replied drily, "You know how they are made, I'm sure."

"Of course I do," Sengoku replied heatedly. "Just where did you get a child from?"

Garp sighed, "Why is everyone asking the same questions today?"

"Garp!"

Garp held Yang in front of him, presenting her to the Admiral like a shield.

"Yang, meet Admiral Sengoku. Sengoku, meet my little Yang."

Sengoku was at loss for words, as he stared at the child in front of him. It took him a moment to process what Garp had just said.

"You've had another child? After what had happened with your other three?" Sengoku said. The mere idea seemed to shock him.

Had he not been holding Yang at that moment, Garp would have obviously taken offense and done something about the insulting tone of his friend's exclamation. But with his hand's bound, he just answered.

"This is my granddaughter!"

"Granddaughter... which one of your troublesome children managed to procreate? The terrorist, the drunk or the pirate?"

"She's Raven's daughter!"

He really didn't like the tone of this conversation and he was just about to hand Yang over to Bogard to dish out some much-needed justice by himself.

Garp was well aware that all three of his children were less than perfect. Raven had just proven this by abandoning her daughter. But that didn't mean that Garp loved them any less.

"This is a nightmare and you know it. Fleet Admiral Kong will not be happy about this at all. Raven's bounty has just been doubled after she robbed one of the Celestial Dragons! And now she has a child!"

"No one will touch my Yang," Garp declared hotly.

Sengoku shook his head, as he took a step closer, to inspect Yang more closely. But the little girl took this as an obvious invitation to grab the Admiral's long beard and pull as hard as she could. Sengoku howled in surprise.

Garp laughed loudly, as he watched his granddaughter's antics. Not even out of her diapers and she was already a natural at annoying Sengoku. This has to be a family trait!

"Garp, tell her to stop!" Sengoku demanded.

Garp didn't react at first, but Bogard was quick to help the Admiral out. But even the Captain needed a bit of time to lure the child's attention away from Sengoku's beard.

"You know that I have to report this to the Fleet Admiral?" Sengoku said, increased his distance from Yang. "But it is up to you what I will tell him. I owe you that much, I guess."

"Tell him... tell Kong that Vice-Admiral Monkey D. Garp will be unavailable for long-term missions in the near future. Tell him that I will raise my granddaughter myself and turn her into the best Marine this world has ever seen. She will not follow her mother's path."

Sengoku nodded, somewhat satisfied with this answer. Maybe it would even mollify the Fleet Admiral. If not... well they would find a way to make this happen

Note:

That should be enough for an introduction. So for this story, we assume that Garp actually had more children than just Dragon. As the father of Qrow and Raven, Garp obviously has a problem with raising his own kids. A pirate, a revolutionary and a drunk... But he has another chance. A granddaughter to raise. And he has no choice but to raise her himself. With Sengoku knowing about her, he can't hide her away like he did with Ace and Luffy. The World Government has a habit of blaming the parents' crimes on the children, so he has to keep Yang close to keep her safe from the fallout of Raven's shenanigans.

I chose Yang as Garp's grandchild exactly because of her troubled family background, which seems to fit better with Garp's current family. Ruby's mom seemed a bit too tame and good to be an offspring of Garp the Fist. And Garp's fighting style works better for Yang.

This also makes Yang the cousin of Luffy. They will have so much fun when Yang starts hunting him. They will, of course, meet as children at one point.

At the moment I have no plans to give either Ruby or Yang a Devil fruit. Yang especially works better as a pure Haki user, like Granpa Garp. If I find a Devil fruit that would work well with Ruby, though, I might consider giving her some special abilities.

Other RWBY characts will join either of the sisters, but neither of them will join Luffy's crew.

I want to be really honest here, I haven't really been an RWBY fan before writing this story. I actually had to binge-watch it with my friend to see it all for myself. My honest opinion here is that the show would have worked better as just a comedy show, the way RWBY Chibi does it. The dramedy attempt doesn't really work that well after the third season, but that's just my opinion. But thankfully, my focus will be on the One Piece world.