A/N: This is my first story so sorry if I'm not that good at writing. Also, I don't know if my grammar is good or not. Anyway, this story is about how Shanks could change many things in the future of the Straw Hats by being Luffy's mentor.

"_"-in quotes means talking

'_'-means thinking

Chapter 1: An Apprentice

It is the day after Shanks lost his arm. His original plan was to just leave the town. He had already been there long enough. What if he put it in danger?

'Maybe I could do it somewhere else?' thought Shanks.

He was thinking about what Benn told him the day before…

(Flashback)

"Listen Shanks, the kid has potential. He just ate a devil fruit, and he's very stubborn too. Maybe you should take on an apprentice," said a smirking Benn Beckman.

After Benn said this, Shanks spit out the sake he was drinking.

"Are you crazy Benn?!" retorted Shanks indignantly.

"Why? You like the kid and eventually you'll grow old. Think of it: The New Age. Besides, he's going to continuously get himself into a lot of trouble. Something bad could happen to him or his nakama if he's not ready for it," replied Shanks' first mate. He said the last sentence with a grim undertone to make his point.

"I believe in The New Age but he needs to work to get to the top. I shouldn't just hand it to him. I care for Luffy but he can take care of himself," said Shanks, suddenly serious.

"Just consider it Shanks. I'm not telling you to teach him everything you know or to take him to The New World. I'm just saying you should help him out a bit," finished Benn before he went inside the boat.

(Flashback End)

'Dammit, why does he have to be so convincing?' thought Shanks. He knows Luffy is the kind of person to get into a lot of trouble. He couldn't just leave him to his own resources. Besides, what if the marines found out about his father? He would be in serious trouble.

'What am I going to tell him? He already said he doesn't want to join me on my adventure. Garp probably knows about me talking to him. If not he'll tell him soon,' thought Shanks.

'Maybe I should just go back to the island and train him in secret while his grandpa isn't there. I wouldn't want to fight someone as strong as him," thought Shanks while shivering at the idea of fighting a grandpa nicknamed: Garp the Hero. He may be strong, but Garp cornered The Pirate King on many occasions.

The captain of the Red Hair Pirates decided he should just go to sleep. He made his decision already so there was no point in fussing about it.

(The Next Day)

"Alright crew! Time to get up! We're making a U-turn back to Luffy's home town," declared Shanks early in the morning.

"What?!" came a chorus of replies from the crew. "Weren't we returning to The Grand Line?" asked a random crew member.

"You can blame Benn for this," mumbled Shanks glaring at his first mate.

After this the crew began their journey… back to the place they just came from. The sky looked as if it wouldn't rain for a few days. It was pleasant weather.

Before they were in sight of the island, Shanks decided to tell everyone that they shouldn't be spotted on the island. To avoid being spotted, Shanks told his crew to take the boat around the island to an unpopulated area.

As they were going around, they noticed a river big enough to go through.

"Alright we'll go through the river to an area in the dense forest and stay there. From there, I will go alone to the town," said Shanks.

"Mind telling us what's going on captain? Why are we returning?" asked a confused Yasopp. Lucky Roo was too busy eating a large chicken leg to say anything. He settled for giving a grunt of agreement.

"I'll tell you later, I don't feel like explaining right now," retorted Shanks.

Later that day Shanks began to make his way to the town. The jungle was really dense. Along the way he even had to scare off a few creatures that tried to eat him. This place was really beginning to annoy him.

"I'm almost there. I was starting to get really hungry… maybe we should throw a party when I get back to the boat," said Shanks to himself.

After a few more minutes of walking he finally made it to the town. It is now night so most people are sleeping. He decided to put on the cloak he got from the boat. It has a hoodie so it covers his face well. Right now he is standing outside of the house where Luffy stays with the mayor.

This is before Garp took Luffy with Dadan.

After a moment of consideration, Shanks decided to climb up to the window of the room where he sensed Luffy. It was easy for him to sense him using Haki.

"Luffy. Luffy. Luuuuffffyyyy," whispered Shanks from outside the window. Shanks tapped the glass to try to wake him up. Nothing was working no matter how much noise he was making. Finally, Shanks opened the window and went inside.

'How should I wake him up?' thought Shanks.

After a few more minutes Shanks flicked Luffy on the forehead with a little Haki.

"Wha-" started Luffy but Shanks quickly covered his mouth.

"Come with me Luffy I'll explain everything when we're outside," said Shanks. Luffy just nodded and began to follow. He doesn't know it is Shanks but Luffy is an idiot so he just followed.

Once they reached the forest they stopped walking. Shanks removed his hood now that they were out of site.

"Shanks? I already told you I won't go with you on your journey!" exclaimed a surprised Luffy. He was now really confused.

*sigh* "I'm not going to take you anywhere. Would you like me to be your teacher for a while?" asked Shanks.

"Why? I'm already strong," declared Luffy.

"Luffy, there are a lot of people that could take you down without even touching you. I just want to help you become a strong pirate in the future," retorted Shanks.

"Okay," agreed Luffy.

"Alright then follow me. We'll be walking for a while," said Shanks.

On the way there Shanks noticed Luffy looking at him sadly. He didn't know what the reason was but he'd find out.

"Luffy, what's wrong? You look sad," said Shanks in a caring and serious tone.

"I'm sorry for your arm…" said Luffy quietly. He felt guilty each time he thought about Shanks losing his arm for him.

"Hahahaha! Don't worry about it Luffy! I made my own decision. It wasn't your fault," responded Shanks.

"O-okay," said Luffy before he ran forward and gave him a hug. He began to cry. It took a few minutes for him to finally stop crying. When he did, they began to walk again.

After about an hour they finally made it to where the ship is located.

"We're back!" Shanks said.

After greeting their captain The Red Hair Pirates noticed Luffy.

"Captain what's Luffy doing here? You're not actually going to bring him along are you?" asked Lucky Roo. He was worried. 'Has the captain gone insane? We can't take Luffy to The Grand Line,' thought Roo.

"Well I guess I should finally explain," started Shanks, "Benn suggested I should take on an apprentice," he finished.

The crew just looked at him blankly, expecting him to laugh any minute now. When it didn't happen they began their interrogation.

"What?"

"Why?"

"Are you kidding?"

"We're not taking him with us are we?"

"No we are not going to take him to The Grand Line that would be stupid," said Beckman.

"We're not going to leave this island for a while. Luffy is a troublemaker. He will need all the help he can get once he becomes a pirate. Especially once he goes to The Grand Line," explained Shanks.

"Why Luffy? Couldn't you just choose any other kid?" asked Yasopp.

"I see potential in Luffy. He has a strong will power. By the way, isn't Usopp in the East Blue too? What if he joins Luffy's crew?" asked Shanks.

"My son would probably want to be captain but it's possible," agreed Yasopp while imagining his son's antics. It seemed really funny to him.

"Hahaha!" laughed Shanks loudly.

"Hey! When will we start my training?" asked Luffy. He was beginning to get impatient. 'Jeez, when old people start talking they talk forever!' thought Luffy.

"We are actually going to start tomorrow. Today I'll explain what I plan to teach you," declared Shanks.

"Can't we start now?" asked Luffy. He wanted to start his awesome training already.

"No, you're too tired to train properly. Anyway, I'm going to teach you some swordsmanship, hand-to-hand combat, and how to use two types of Haki," summarized Shanks. He had already planned out his training.

"I'll teach him battle tactics. You can't always charge in to situations. When you are with nakama you could put them in danger," added Benn. 'He'll need to know battle tactics if he wants to eventually face off with Sengoku,' he thought.

"Part of your training will also be to get to this location every day. There are some creatures that might want to eat you long the way," said Shanks.

Luffy paled a little at this. He didn't want to end up being food for creatures at such a young age!

"It's getting late now. Should I take you back home?" asked Shanks nicely.

Luffy nodded in the affirmative. After that, the two began to walk to the mayor's house. Once they got there Shanks stopped walking.

"Luffy, tomorrow I want you to be at your new training ground at 10 in the morning. I don't want anyone to know I'm here. Tell the mayor that you're going to walk around or something. Also, NEVER tell your Grandpa I'm training you," said Shanks.

"Ummm… okay," agreed Luffy. "I'll see you tomorrow Shanks!" said Luffy before going inside.

As Shanks was walking off he thought to himself, 'I hope this works out well.'

(The Next Day)

Luffy woke up at 8 in the morning. 'Wow it's really early. Will it be like this every day now?' pondered Luffy. 'I'm going to be really strong soon!'

After rubbing the sleep out of his eyes he began to get ready. An hour later he was ready.

"The mayor is still asleep so I'll leave him a note that I went to walk around by the neighboring towns," said Luffy to himself. After writing the note he left the cabin.

It took him an hour to reach the place where Shanks told him to be. In other words, he was there at 10. He managed to avoid any creatures along the way.

"Hi Luffy! You made it on time," said Shanks.

"Why do you have to be so far from town?!" asked a tired Luffy.

"I don't want to be spotted," replied Shanks.

"Whatever…" retorted Luffy. Then he remembered Shanks was going to train him. He was really excited to learn something new. "What are we going to do today?" he asked.

"First we're going to a nearby town to get you a sword. There is a good blacksmith around here," replied Shanks.

"I'm going to get a sword? That's so cool!" said Luffy.

"A sword isn't a toy Luffy. Be careful whenever you use it," lectured Shanks.

"Okay I will," said Luffy trying to be responsible. On the way to a nearby town Luffy had a big smile on his face.

After walking for about twenty minutes they finally reached the town. After another five minutes of walking in the town they entered a shop.

"We want to buy a sword!" yelled Shanks cheerfully as they walked in. A man walked over to them after a few seconds.

"I'm sorry but we're out of swords. A man just came by from a dojo and bought the swords. He said his students were ready to practice with real swords," replied the old man.

"What if I put in a custom order?" asked Shanks hopefully.

"I'm not that good at making swords. My son usually makes them and he's on vacation. I know how to make other weapons," offered the old man.

"Can I choose a different weapon then?" asked Luffy. He really didn't want to leave empty-handed.

"Well… okay you can have a look around. I know how to use some other weapons," said Shanks. He knows how to use a few weapons, but he prefers his sword.

"Thanks Shanks! Come on!" he said as he started to drag Shanks around the store. After looking around a little he saw something that interested him. "What are these?" he asked.

He was pointing to a pair of weapons. Each has three prongs. The longest prong is about a foot long. They also have a handle that is big enough for only one hand to hold it.

"Those are sai. I know how to use them but they've never been my favorite weapon," said Shanks. "You like them?" he added.

"Yeah they look really cool!" said Luffy.

'He ate a paramecia fruit that probably involves a lot of hand-to-hand combat: the Gomu Gomu no Mi. The sai also involve getting close to fight. It seems like a good weapon for him,' thought Shanks.

"Did you choose what you want yet?" asked the old man as he approached them.

"Yeah I want these!" yelled Luffy.

"No he doesn't. He wants the best pair of sai you have. I don't care what the price is. I'm going to pay for them," said Shanks. The old man looked at him questionably. He didn't know if he could actually pay for them. When he came back he was holding a golden case.

"This is my best pair of sai. The Longarm Tribe helped me make these. My wife is part of their tribe so sometimes they help me make great weapons," he said as he began to open the case.

Inside are two sai. They both are made of a black metal and have a handle that appears to be made of strong and durable leather. It appears gold in color. The end of each handle is made of the same black metal as the prongs. All three prongs are very sharp, unlike some sai in which only the middle prong is sharp. The only difference between the two sai is that one has a long, red dragon on the middle prong while the other has a long, blue dragon on the middle prong.

"The name of the sai with the red dragon is Kagutsuchi (god of fire). The name of the sai with the blue dragon is Watatsumi (god of the sea). Each one costs 300,000 beli so combined they cost 600,000 beli," he said expecting Shanks to protest the price.

"What makes them so special besides the good quality?" asked Shanks. He expected them to be this expensive.

"The Longarm Tribe said that when they are wielded correctly they can 'Breathe' fire and water," he responded. This made Shanks' eyes go wide.

"I want to be able to make them use fire and water. Since they can breathe can they eat meat too?" asked Luffy. They seemed like awesome sai.

"They can't really breathe and they can't eat. He just meant they can generate fire and water. Anyway, I'll pay for them," he said as he took out the requested money.

They got back to the training area about an hour later. They took so long because they ate at a small restaurant before heading back. The first thing he made Luffy do is exercise and build up strength. Eventually he would teach him how to use his sai. The last thing he will teach him is how to use Haki. He won't teach him how to use Haki until he has a good mastery of hand-to-hand, how to use his sai, and tactics.

(About Eight Months Later)

During the eight months that passed, Luffy learned a great deal of things. He was a quick learner. He could still improve with his sai, but he knows enough to be considered a master. He got really good at hand-to-hand combat. Before he could improve in hand-to-hand combat he had to learn how to make his devil fruit useful. It didn't really take long. Every day during breaks Benn taught him tactics and new things. If he had a bounty, Shanks would place it at 30,000,000 to 50,000,000 beli.

The day before this day Luffy turned eight years old. Because of this, Shanks decided to teach Luffy something special. He would've done it on the exact day of his birthday, but he was celebrating with Garp and the town people.

"Luffy, today I will teach you about two types of Haki," said Shanks.

"What's Haki? It sounds boring. Will it make me stronger?" asked Luffy.

"Haki is the power of ambition. Everyone has it and you can use two types of Haki by training. These two types are Kenbunshoku Haki and Busoshoku Haki. Kenbunshoku Haki is also known as Color of Observation Haki. It allows you to sense the presence of others even if you can't see them. With enough practice you can predict your opponents' moves shortly before they do them," he replied as he began to walk.

Luffy began to follow Shanks to where he was going. Suddenly Shanks stopped.

"There is a large tiger behind me. Don't do anything or interfere in any way Luffy," Shanks said. After he finished talking, a large tiger charged at him from behind. Luffy began to panic but he didn't attack the tiger because Shanks told him not to.

Suddenly the tiger swiped at Shanks from an angle to his head. Shanks dodged it by ducking while he had his eyes closed. He continued to dodge its various attacks without even looking.

"Awesome!" said Luffy with sparkling eyes.

"Busoshoku Haki is also known as Color of Armaments Haki. This is like an invisible armor that you can use as a defense or to attack. It can make your attacks with weapons stronger by putting it in them. You can also make your normal attacks stronger. You can use it to attack logia users or exploit the weaknesses of devil fruit eaters. It's what I used to wake you up a few months ago. Your Grandpa uses it a lot too," he explained as he turned around and hit the tiger with a force that shot forward from his hand.

"The last type of Haki cannot be awakened by training. You have to awaken it by strengthening your spirit. This Haki is Haoshoku Haki or Color of Conqueror Haki. This is a rare kind of Haki. Many leaders in the world have this kind of Haki, me included. It can be used to intimidate opponents. It can be controlled but you can't train it. To enhance it you have to develop yourself," he finished his explanation.

After he finished explaining, the tiger got up and attacked Shanks again. Shanks simply used Haoshoku Haki to intimidate it and knock it out.

"Wow! You're so strong. Are you going back to The Grand Line eventually?" asked Luffy. He was clearly impressed. "I want to be able to do that," he added.

"I'm not going back to The Grand Line until your learn how to use Haki. I don't know if you have Haoshoku Haki but I think you do. Once you awaken it, be careful because you can intimidate innocent people if you can't control it. Get someone to teach you how to control it," said Shanks.

"Okay I will Shanks," replied Luffy.

(Summary of Next Few Years)

For the next year and a half Shanks taught Luffy how to use Kenbunshoku Haki and Busoshoku Haki. Luffy got good enough to be able to use both in a fight and even to use Kenbunshoku Haki like if it was second nature. Shanks had to leave when Garp took Luffy to Dadan. Also, Shanks decided it was time to go to The New World. He wanted to make his name known to everyone in the world. How would people react if Red-Hired Shanks came back after all his time absent without an arm? Anyway, over the next few years, Shanks became a Yonkou of The New World.

A/N: Tell me how you like my story. In my fanfiction Shanks was not a Yonkou when he took on Luffy as a student. He WAS a well-known pirate with a high bounty. I would place him at Jimbei's level. After he became a Yonkou he obviously got a lot stronger.