Warning: Grammar might be terrible. You've been warned.
Author note: I'm a fan of Godlike and a little emotionless Naruto, so yeah no stupid and goofy Naruto here. Actually, I write this fic inspired by "Naruto Uchiha: The Sage" written by The Omnipresent Sage. You should read that as well, you might love it.
A Promise between Immortals
Chapter 1: Prologue
Tenrou Island, x783
Being alone was lonely, moreover for the likes of Mavis who liked to surround herself with laugh and cheers. Ever since she got cursed into immortality and got separated from her body, she lived alone in the secluded island of Tenroujima, her home. Though, loneliness was not something she didn't familiar with, in fact since her childhood, loneliness was her only company; the feeling she understood the most. It was until she reached twelve or thirteen that Zera started to be friended her, after all, she along with Zera were the only survivor of the guild war that annihilated her so-called guild; the girl had no choice but to live with her or else she could die, but by the times went on, the two became a very good friend.
A year after that, she met her second and third friend: Naruto Uchiha and Zeref Dragnel, two immortals that wandered around the world.
A beautiful smile graced her thin lips when gold particles appeared under a big tree and started to form a silhouette of person she so familiar with.
It had been four years since the last she saw him. His appearance was exactly the same as four years ago: long blond hair reached his back, onyx irises, black anbu pants, black shinobi boots, black shirt covered with grey yukata, and a stoic face. She expected that much from him, but she really preferred him to smile, not that she didn't like his stoic face, but his smile was something she cherished the most.
Mavis walked closer towards her teacher, her friend, her.. love interest, who was leaning against a large tree while gazing at the blue sky. "You said you'd visit me more often," she said in a sternly voice.
"I did try, but something held me from visiting you."
"I never think that 'something' could hold the great Naruto Uchiha."
The man brought his head to stare at her, his lips were twitching before it turned into a little smile, "I miss you too, Mavis."
A smile graced beautifully on Mavis lips, she wasted no time as she lunged herself to hug her blond immortal. Even though her body was just ethereal body, but she could touch Naruto and so did Naruto. Mavis buried her face on his chest, she really missed the warmth his body provided just for her, she missed his smell, she missed his gentle touch; Mavis missed him so much.
"Where were you these four years?" Mavis asked as she gazed at his onyx eyes, she was interested in knowing anything he had done in the late years.
"You do still remember about the origin of chakra and magic, right?"
"Yes, shinju and Ootsutsuki."
"About five thousand years ago two of them came to earthland, and two years ago another one came to me."
Her eyes widen at the mentioned of the people who called themselves god, it was a bad news, anything involving the Ootsutsuki was a threat to the world. Their existence itself was a danger to all human, no, to the existence in the whole world. Since the birth of magic from the one magic or the origin of magic, no one posed a threat more terrifying than the Ootsutsuki, not even Zeref when he snapped, not even Acnologia the apocalypse dragon. So hearing the news about that particular being, instill fear in her gentle heart.
She got back to her sense when she felt her hair being stroked, he gave her a reassuring smile that eased her worries, "Don't worry Mavis, I already turn him into chakra pill."
"Chakra pill?"
"Oh, I have yet to tell you about that. Anyway, chakra pill is similar to chakra fruit: the origin of magic. But chakra fruit is purer and far superior than chakra pill, also chakra pill cannot diverse into ethernano like chakra fruit did."
"Where is it, can I see?"
"I keep it somewhere safe, I'll let you see it the day you agreed to merge with your body. You have yet to tell me as to why you refuse to merge with your body, I can suggest some cases, but I prefer to listen directly from you. Will you be kind enough to tell me, dear?"
"Nope."
"How kind of you, my dear."
Mavis smiled, she brought both her hand to captivate his cheeks. Blood arose to her cheeks, redden it in pink color. They stared toward each other, emerald met onyx. Slowly but steadily, Mavis captured the blond lips with hers, she closed her eyes enjoying their shared kiss. It was not kiss based on lust, it was a gentle kiss that full of emotion, the kiss that symbolized of how much they loved each other, how much they meant to each other.
A moment later Mavis broke the kiss and gave her immortal blond a very beautiful smile she could offer, "I really miss you, Naruto." She said.
The blond returned the smile and kissed her forehead softly, "So do I, dear."
"So dear, when will you join my guild? You did say that at some point in the future, that was sixty years ago. You still remember it, right?"
"Perhaps tomorrow, for now let us spend the day."
"Like usual?"
"Yup, like usual."
Later on
How many years he had lived his life? He safely could say it was around five thousand years, more or less. He already lost count on the exact number of years, perhaps because of the loneliness he felt. He had no one to talk to; all his loved one already passed away so long ago, leaving him alone with all chakra. That was not true at all, in truth, he was the one who left them since he was no longer human. He was the one who made that choice. He had absorbed Kaguya along with black Zetsu, he then sealed Juubi inside his gut that made him the ten tails Jinchuriki; which in the end made him immortal.
To ensure the peace in elemental nation, he turned himself into Shinjuu and begun absorbing chakra from all human. Hundred years after that not even a single human possessed chakra, thus birthing another chakra fruit.
Naruto still didn't understand how that chakra fruit could be vaporized into the atmosphere and diverse itself into what people knew as ethernano. But one thing was sure: the summon beings, except dragon, were all dead being poisoned by the ethernano. That explained, excluding him, why the dragon became the strongest being in existence.
Naruto sighed, he just hope that it was not something done by the otsutsuki, after all, they're the one who brought the seed of shinjuu upon elemental nations that now known as Earthland.
Naruto brought his attention back at the sleeping Mavis. As a spirit, the only one who could touch Mavis was him, not that he would allow anyone to touch her. Mavis was his.
"I can sense Mavis, she is with you."
Naruto shifted his head toward his guest who was sitting and leaning against a tree right in front of him. "Zeref," Naruto muttered before returning his sight at the beautiful face of Mavis spirit who was sleeping on his lap. "It has been awhile," Naruto stated as he gazed the man.
"Yes, it has."
Zeref probably wanted to know more about the opponent he fought two years ago, he would not tell though, the guy could ask if he really wanted to know.
"Whom you were fighting to? His/her power was closer to mine, it makes me curious."
"The intruder, an Otsutsuki."
"I see. So they really exist. Do you know how many they are outside there?"
"I don't really know. That is why I disagree with your desire to die, you could help me to eliminate them. From the late three Otsutsuki, two of them were weaker than you, and another one was slightly on your level. We could say that only you, Acnologia, and I will be able to kill them. I might be wrong though."
"I see, I will reconsider my choice."
"You are leaving," Naruto stated as he watched the black mage stood and walked away.
"I'm needed elsewhere."
Naruto shook his head and returned his sight toward Mavis sleeping face, he brought his right hand on her cheek, a beautiful smile found it's place on his lips. "Such innocent," he said as he closed his eyes and joined his Mavis.
Two days later, Magnolia
It never ceased to amaze him how the people of this era lived their carefree life, perhaps it was because killing was something people loathed the most and the fact that dark guild didn't operate in the crowded town added to the list of reasons that made people felt safe. But perhaps because this was Magnolia he was walking in, there were no dark guilds who were stupid enough to play in the fairy tail's town; after all, the guild known as the strongest guild in all Fiore.
Naruto stared at the big door in front of him. It was the second times he stood in front of Mavis's Guild building, the first was when she just founded the guild around ninety years ago. It was so different compared to the guild back then, the feeling though somewhat felt the same, very fairy tail.
He rose his hands and pushed the big door slowly, the sight that welcoming his eyes were something he expected. Laughs, cheers, fights, yells, and some other absurd things; but the expression on their face was pure happiness. Naruto could not help but smile, the guild was the very personification of Mavis.
He entered the guild and walked toward the short old man that was sitting on the bar table, the old man had the biggest magic reserve in the whole guild, it indicated that he was the guild master, possibly. Before he reached the bar, a chair was thrown toward him but it crumbled and burned into ashes before hitting his head. No one paid attention except the white haired woman who was acting as a barista and that little old man, he could see their surprised face for a moment but Naruto didn't mind it. Soon he reached the old man and the woman, he offered the woman a little smile which she returned and then he focused his eyes on the old man.
"I presume you are the guild master, am I wrong?"
"No, you're right. I'm the third guild master, Makarov Dreyar. Who are you, young man?"
"Naruto. I wish to join your guild, no, Mavis's guild."
The old man eyes slightly widen, "You know the first master?"
Naruto smiled, "Mavis is a beautiful woman with a gentle heart, perhaps this guild is built based on her personality. Even now I can see it, her beautiful smile still exists in this guild."
"I see. Please follow me, there is something I'd like to discuss."
"Lead the way."
Naruto followed Makarov as he was heading to the second floor toward his office. Soon they entered the office, the old man wasted no time as he sat on his chair and motioned him to sit right in front of him. Naruto just did that, though he was not looking forward to indulge in whatever the old man would ask him; he would tell what he wanted the old man to know.
"The way you spoke of the first master, it looks like you know her at personal level. It is hard to believe since she lives long time ago while you're just a young man, I might be wrong. Thus I've a question, how old are you?"
"I met her at Tenrou island years ago, you could say that she is still there. Perhaps that is her spirit I was talking to. Anyway, she asked me to join her guild." Naruto smiled, "About my age, am I looked that old to you, old man?"
The old man seemed to be occupied with his thought, perhaps he was thinking about Mavis spirit? That would bring question about Lumen Histoire, but he doubted the old man would ask about that.
"I see. If the first master asked you to join the guild, that's mean you are a good person. Welcome to Fairy Tail, please meet Mirajane, the white haired girl you smiled at earlier. She will stamp you the guild symbol which will make you a member of the guild. But before that, please tell me your full name, your main magic, and your former town so I could report it to magic council."
"That will do. Naruto Uchiha, I can use many magic such as elemental magic and some. I lived in Tenrou island, Mavis's hidden library."
"That explain why we never saw you when we were there, even I don't know where the first master's library is. Say young man, what is the relationship between you and the first master? Perhaps she is your teacher?"
"That is our little secret, old man."
The old man frowned, but he nodded nonetheless. Privacy was privacy, if people decided to keep it secret then no one had the right to know it.
"If that's all then I will see this delightful white haired girl."
Naruto didn't wait the old man's response as he disappeared and reappeared next to the white haired girl at the first floor, which surprised the girl as she let loose a yelp scream much to his amusement.
"I take it you are Mirajane?" Naruto asked, his eyes were glued to hers. He admitted that the girl was quite the beauty, but Mavis was still the best.
"Yes, I am. Can I know your name?"
"Naruto, Naruto Uchiha."
"Then Naruto, since you are here that's mean master already finish questioning you?"
"Yes, he has."
The girl clasped her hands, "That's good," she said. "Where you want the guild symbol to be stamped at, and what color?"
Naruto folded his left yukata's sleeve along with the shirt's sleeve, "Here, black with crimson outline." He said and showed the girl his left shoulder.
The girl cheerfully did her job, "It's done. Welcome to Fairy Tail." She smiled happily.
Naruto could not help but smile as well, perhaps this was indeed the right time to join the guild, as the third generation of Fairy Tail.
End Prologue.
Naruto was the one who taught Mavis magic, not Zeref. In this story, Mavis and Zeref didn't have any special relationship.