A.N: This is my fourth OP story and my second OP one shot. Sorry if there is some grammar mistakes and sorry if chacraters are OOC (Robin is just so damn hard to write about). And this one shot doesn´t really have a timeline. Enjoy!

Disclaimer: I don´t own One Piece.

Like a little brother, like a big sister

It was a beautiful day. Everyone were on the deck, doing things what they saw most fitting to the day. Robin was reading her new book, Nami was sunbathing, Sanji was just staring at Nami like a fool, Zoro was napping and others were fishing.

"Oh, I got one! Yohohoo!" Brook laughed when he caught a fish.

"Suupeeer!" yelled Franky.

"Wow, it´s a big one!" Luffy yelled and laughed. He and Brook put it in to the aquarium and then they went back to fishing. Brook was about to put a new bait on to the hook but then he noticed that all the worms were gone from the bucket.

"I will go get more worms", he said to the others. He went inside to get the worms, but soon he came back waiving his hands around and yelling: "Intruder! Intruder! We have an intruder!"

This put everyone moving. Usopp and Chopper started yelling and running around the deck, Sanji went to stand in front of Nami and Robin that he would protect them from the intruder. Zoro smirked and stood up and prepared to fight with Luffy and Franky.

A couple of minutes passed, but the intruder still didn´t come on to the deck.

"Umm… Brook, are you sure that there was someone there?" Usopp asked. He really hoped that Brook would have seen wrong.

"Yes there was, but he was sleeping." Brook said.

"You should have said that earlier!" everyone except Robin yelled at him.

"Yosh! I´ll go there and kick his ass!" Luffy yelled cheerfully.

"Wait, Luffy!" Nami yelled. Luffy turned his head towards Nami.

"What is it, Nami?" he asked.

"We don´t know anything about this intruder. You can´t just go there when you don´t know anything about him." Nami warned her captain.

"Nami´s right, Luffy." Sanji said. Usopp and Chopper agreed with him.

"Then what should we do?" Luffy asked, crossing his arms.

"I can check if I know him with my powers", Robin interrupted. Everyone agreed, so Robin touched her eye. And when she did that, an eye appeared to the ceiling of the room where then intruder was. Robin studied the intruder, who was a tall, muscular man, for a moment. She was sure she had seen him somewhere. And then, it clicked.

"This isn´t good! That tattoo and that face, he´s-" Robin´s thoughts were interrupted when the man suddenly opened his eyes. Robin took her hand quickly away from her eye and said: "Everyone, prepare to fight! That man´s awake and he´s really dangerous!"

Nami blinked.

"Do you know him, Robin?" Nami asked, confused and a little bit scared. Robin shook her head.

"I´ve never met him in person, but he´s a wanted man. His bounty is 350 million beri." Robin told. Everyone went silent.

"350!" they yelled suddenly.

"Quiet, everyone, he´s coming!" Nami whispered when she heard footsteps. Chopper sniffed the air.

"Strange… this intruder smells pretty familiar." he thought. He jumped when the door was opened. Before anyone was able to do anything, Luffy had already thrown a punch at the man. The man docked it easily and pinned Luffy down to the floor.

"Geez, Luffy, what was that for?" he asked. Luffy looked at the man and then yelled: "Ace!"

"Ace! Fire fist Ace from White Beard pirates!" Franky asked in disbelief. Now they were in deep trouble. Chopper and Usopp fell on to the floor. They were so relieved.

"Phew, it´s just Ace." Usopp muttered. Sanji, Nami and Zoro stared at Ace for a while and then they all started to laugh.

"Good damn, Ace! Don´t scare us like that!" Zoro yelled between his laughs.

"Scare you? What did I do?" Ace asked, still holding Luffy down. Others just continued laughing.

"Hey hey, could somebody explain what the hell is going on!" Franky yelled, lifting his sunglasses to his for head. Before anyone could say anything, Ace let go of Luffy and stood up.

"My name is Portgaz D. Ace. Nice to meet you", he said to Franky and held out his hand.

"That´s not what I asked!" Franky yelled as an answer.

"So Ace, I heard you are worth 350 million beri." Nami said, possibly just trying to start a conversation.

"Aaargh! Nami´s planning on giving Ace up to marines!" Luffy yelled immediately. Nami punched Luffy.

"No I´m not, you idiot!" she yelled.

"Do they know him?" Robin asked from Sanji.

"Yes they do, Robin-chan. Ace is Luffy´s older brother." Sanji explained. Franky and Robin looked at Ace, then at Luffy, then back at Sanji.

"Are you serious!" Franky asked. Sanji nodded.

"Suupeer!"

Robin didn´t say anything. She just watched as Ace told to others how he had tried to find a ship where he could escape from the island and had found theirs, so he had hopped in and had decided to take a nap.

"Just like the stupid Marimo", Sanji said and ended up fighting with Zoro.

"Let´s have a party!" Luffy yelled. Everyone agreed to this.

XXXXX

It was already late, but the party was still continuing. Robin watched as Ace told to the others what kind of stupid things Luffy had done when they were kids. And when Luffy tried to tell them something funny about Ace, Ace whacked him before he could do that. Luffy complained that Ace was mean and then Ace and the others laughed.

"Is something wrong, Robin?" Nami asked as she passed by Robin. Robin shook her head.

"No, Nami-san." she lied. Nami looked at Robin for a moment more and said then: "Well, if you say so."

"Nami?"

"Yes?"

"Do you have any siblings?" Robin asked from the younger woman, who blinked in surprise.

"Yeah, I do. I have a big sister named Nojiko." she answered. Then it was her turn to ask: "Why do you ask?"

Robin turned her head away.

"No reason", she lied again. Then Nami left. Robin looked at Ace and Luffy again. When she was a kid, she had always hoped that she would have a brother or a sister. Because then she wouldn´t have had to be alone. She was envying her captain for having a big brother.

A big brother who took care of him, a big brother who loved him. A big brother who knew his deepest secrets, a big brother who trusted his own deepest secrets to him. They had gone through so much when they were kids, through good days and bad days, trusting each other. She envied it all. Sure she had friends now, but she didn´t have anyone who she could share stories from her childhood with.

"I really wish I would have had a sibling too… it just would have made my life a little happier." she thought sadly.

"Is something wrong Robin? You look sad", Robin heard a childlike voice say from her right side. She looked down and saw Chopper.

"No", Robin lied again. Chopper sat on the floor next to Robin and said: "I don´t believe you."

Robin blinked in surprise. Usually Chopper believed everything that was told to him, so why not this time?

"You´ve been watching Ace. Did he scare you?" Chopper asked.

"I was sure no one would notice", Robin thought.

"No, he didn´t scare me. I was just… thinking about things." she said. She didn´t really want to talk about this. She didn´t want to make Chopper to worry.

"What kind of things?" Chopper asked. He was the ship´s doctor, so he cared about everyone´s well being. If Robin was sad then he wanted to cheer her up.

Robin sighed. She might as well tell him.

"I was just thinking what kind of my life would have been if I had have siblings like Luffy does", Robin explained with a sad smile on her face.

"I think I know what you mean", Chopper said.

"Is that so?" Robin asked. Chopper nodded and stared at the floor.

"Most of the reindeers have siblings. Maybe I did, too. But I was always left behind because of my blue nose, so I never got to know." he told.

"I see", Robin said. The little reindeer did have a point.

"But it doesn´t actually matter anymore", Chopper added. Robin raised an eyebrow.

"May I ask why is that?" she asked. Chopper blushed and said: "Because you, Robin, are like a big sister to me." He had noticed this already in the Devy back fight, but he didn´t have a chance to say it until now.

Robin´s eyes widened. She was like a big sister to him? But why?

"It´s stupid, isn´t it? I´m a reindeer and you are a human, but…" Chopper couldn´t finish. Yeah, it sure was stupid.

"People don´t need to be blood related to be a family", Robin and Chopper turned their heads and saw Ace behind them. He took a sip from his mug and continued: "Me and Luffy aren´t blood related either, we just decided to be brothers when we were kids."

Robin and Chopper stared at Ace.

"Is that why you have manners but Luffy doesn´t?" Chopper asked suddenly. Robin and Ace stared at Chopper for a moment and then they started to laugh.

"A child is always a child", they both thought.

"Oi, Ace! Your brother is stealing other people´s food again!" Sanji yelled while he was trying to keep Luffy in control.

"I´ll handle it!" Ace yelled back and went to help Sanji. Robin watched after Ace for a moment and then she turned her head towards Chopper, who was still sitting on the floor.

"Well I guess he is a little like a little brother to me", she thought. She stood up, picked Chopper up from the floor and said: "Let´s go get something to eat before Luffy eats everything."

Chopper looked at Robin for a moment and then he replied: "Okay."

A.N: Cute? Annoying? Short? Or maybe something else? Tell me your opinion with a review. About Ace´s bounty: I don´t know what it is so I just put something that was higher than Luffy´s.