Natsu walked back to the den alone for the second time now. When he arrived, he just walked over and sat down beside Igneel and Mu silently. Five minutes passed before anyone spoke.

"So," Mu said, "Madara taught you the basics, correct?"

Natsu closed his eyes and let out a long sigh of relaxation. "Yeah, he did. He even taught me his fire release jutsu."

Mu nodded. "I see, well that saves me a lot of time. I have decided to wait a week's time before beginning your training with me. This is to let you catch up with Igneel, as well as for me to go over the best way to teach you." Mu stated.

Natsu looked relieved. "Thanks." Natsu said, before suddenly opening his eyes widely. "Oh! I forgot something!"

Mu and Igneel looked at Natsu with an eyebrow raised. "What is it?/What?" They both said.

"I still need to show you that technique I made!" Natsu exclaimed excitedly.

Igneel smirked. "Yeah, you do. I look forward to it."

Natsu grinned. "Yeah, it's really awesome. In fact it's based off of a technique that was created in the Elemental Nations!"

Mu looked surprised at this. Err... however surprised you can look under bandages. "May I ask which one?" He asked.

Natsu frowned. "I don't know if you would know it... The guy who created it was born after you died.

"Actually, when I was reanimated by Kabuto, all his knowledge of the current situation was implanted in my head, so actually, I might know it." Mu said.

Natsu nodded. "Alright. Well, It's called the Chidori, One Thousand Birds, created by Kakashi Hatake.

Mu looked thoughtful for a second before answering. "Ah, yes. An A-Rank assassination jutsu requiring the user to gather lightning chakra in their palm for immense piercing power."

Natsu nodded. "Well, my technique is like that, however I use flames instead of lightning. Also, mine is powered by magic instead of chakra, since the flames used are from my Fire Dragon Slayer Magic."

Igneel huffed proudly. "What did you name your technique?" He asked.

Natsu grinned. "Well, when I used it for the first time, it didn't sound anything like chirping birds. Instead, I thought it sounded more like Igneel roaring, so I decided to name it Sen Ryu, One Thousand Dragons. Later though, I thought about it more, and decided that since it was based off of Fire Dragon Slaying Magic, I needed to add something more to the name, so now it's name is Ryupou: Sen Ryu, Dragon Art: One Thousand Dragons." Natsu explained.

Mu nodded his head at the explanation. Igneel grinned.

"Sounds like a powerful technique, but what's the difference between it and Fire Dragon's Iron Fist?"

Natsu smirked. "You'll find out tomorrow."

THE NEXT DAY AT A CLEARING

"Alright Natsu, show me this technique you've been talking about." Igneel said.

Natsu formed the dense sand wall that he had originally used the technique on. When it was ready, Natsu turned to Igneel.

"First, I'm going to show you the difference between it, and Fire Dragon's Iron Fist." Natsu said.

Igneel nodded. "Alright." He replied.

Natsu charged at the wall and yelled.

Fire Dragon's Iron Fist!

When Natsu's fist collided with the wall, a huge plume of sand flew up into the air, obscuring vision of the wall, and a loud boom could be heard. When the dust finally settled, the wall had a little crater where Natsu's fist had impacted, with cracks running outwards.

Igneel raised an eyebrow. "That wall must be hella tough to be able to survive that."

Natsu smirked. "Now watch this"

In Natsu's hand was a whitish flame, brighter than any flame Igneel had ever seen. The fire seemed to gather in the tips of Natsu's fingers, before running down, past his hand, and stopping a little bit past his wrist, making it look like a spear. From the flame, he could hear the sound of dragons roaring, as if trying to scare off any enemies Natsu would face. Natsu charged at the wall yet again.

Ryupou: Sen Ryu!

When Natsu hit the wall this time, there was no cloud of sand, so Igneel could see the results perfectly. And what he saw made his jaw drop. Natsu stood there with his arm up to his shoulder buried into the wall, his hand sticking out the other side, it was as if the sand were made of butter. When Natsu removed his arm from the wall, there were no cracks, or any sign of impact other than the hole that went straight through the wall.

Igneel looked at Natsu with wide eyes. "So. How'd you do that?" Igneel asked.

Natsu grinned at him. "It's like the iron fist, except you have to focus all your fire into one point on your hand. For you, I suppose it would make sense for that point to be on the tip of your claw."

Igneel smirked. "Thanks, I'll have it down by the time you're done with Mu, so you'd better have something cool to show me when you get back!" Never in a million years did I ever think that I would be learning from a human...

FIRST DAY TRAINING WITH MU

Currently, we find Natsu walking alongside Mu in the forest surrounding the den. The birds are chirping peacefully, and the forest seems to be humming with life. Suddenly, Mu stops.

"We're here." Mu says.

Natsu looks around, clearly confused. "What do you mean? We're between a bunch of trees..."

"Actually, I'll show you what you're going to be learning from me." Mu said.

Natsu raised an eyebrow. "Oh? And what's that?"

Mu stepped forward, with both his arms pointed straight forward. His hands were facing palm forward, with both his thumbs extended from the rest of their respective hands. All of a sudden, a small, transparent, white box appeared in front of his hands. Suddenly, the box disappeared, only for a massive version to appear over the forest in front of them, encompassing several hundred trees.

Particle Style: Atomic Dismantling Jutsu!

When Mu used the jutsu, smoke filled the entire box, rendering everything inside completely invisible. When the smoke cleared, Natsu's draw dropped. The trees, along with everything else inside the box, were completely gone without a trace. Nothing remained, and where the edges of the box were was perfectly straight.

"As you can see, particle style disintegrates anything down to a molecular level. Nothing can counter it, except your truth seeking orbs." Mu explained

Natsu was having a hard time recovering. The amount of damage this jutsu can cause it insane. It's not even a rinnegan or six paths technique, and yet it has enough power to be one!

Natsu suddenly went into genius mode. "So this is what I will be learning from you?" Natsu asked.

"Yes," Mu replied. "However, this is not the only thing. You are aware of what my nickname was back in the Elemental Nations, correct?"

Natsu thought for a moment. "Yeah, you were known as the Null-Man, right?"

Mu nodded. "Yes, it was because I used a jutsu known as the Dustless Bewildering Cover to completely hide my body and chakra signature. Along with this, I used the Earth Release: Light-Weight Rock Technique to levitate myself. Both these jutsu cost extremely little portions of my chakra reserve, and considering your chakra reserves, I have no doubt that you could most likely use them for your entire life and not run our of chakra.

"Well then," Natsu said. "Let's get started!"

TWO MONTHS LATER

Natsu had finally mastered all of Mu's signature jutsu. Through combining his Dustless Bewildering Cover and Kamui, Natsu could truly become a ghost, being able to fly using Earth Release: Light-Weight Rock Technique. His particle style was on par with Mu's, through extensive use of shadow clones. Once again, however, we find Natsu saying goodbye to yet another teacher.

"Well, I guess I'll see you when I die Mu." Natsu said.

Mu sweat dropped. "Yeah... I suppose you will. But before I leave, I also have a gift for you." Mu said as he pulled something out of seemingly nowhere.

Natsu's eyes opened wide. "Really! What is it!" Natsu yelled happily.

Mu pulled the object in front of him. It was a Sunagakure headband. "This headband was your father's during the war. He must of dropped it near me during the sealing process. I know this can't really comp-" Mu was about to continue, but couldn't, due to the fact that all his air was currently being squeezed out by Natsu's bear hug.

"To me, it means more than the sharingan ever could. Thank you so much." Natsu whispered, with tears in the corners of his eyes.

Mu was shocked. Did someone just hug him? This was certainly new. However despite that, Mu gave his first and only eye-smile.

Natsu looked at him with a shocked expression, before it eventually turned to a smile. "YOU JUST SMILED!" Natsu yelled with a raised fist. "MARK THIS ONE DOWN IN THE HISTORY BOOKS FELLAS!"

Mu chuckled. "Well Natsu, I assume you know the drill by now. I will also be going back. It was... fun... training you. I only have one more thing to say, Natsu. And that is to put your trust in people. Don't live your life alone." Mu said as he disappeared.

Natsu stared at the spot where Mu was just a second ago. "Thank you..." He whispered to himself, as he put on his Sunagakue shinobi headband.

I know the Gaara's headband thing is fucking ridiculous, but I needed a way for Natsu to have a headband. You'll see why later :D