The Lost Dragon Slayer

Summary: As Natsu sacrifices himself holding Acnologia back on Tenrou Island, he leaves Wendy with one final promise. What was this promise and how will it affect Wendy during the years he is gone. She will have to go through many trials and difficult challenges, but will she be able keep her end of the promise in the end?

Chapter 1

S-Class Exams, Tenrou Island, Wendy Age 12

Natsu glared at the enormous beast as it flew overhead, mocking the fairies below. His lips curved down into a grimace as the dragon swirled around and began making its way back to the beaten down group of Fairy Tail mages. It let out a loud, piercing roar that rattled the bones in all their bodies. Standing here now, he finally understood why Gildarts had suffered so much during his battle against the creature. Acnologia was a monster of immeasurable power.

Turning, he looked over at his comrades standing beside him, growling slightly when he noticed the look of terror on many of their faces. Makarov, their guild master, was asleep in Gildarts' arms, completely drained of magic after his attempt to hold the dragon back. He shot a quick glance back at the dragon once more before turning back to his comrades, searing flames bursting to life around his hands.

"Go." he muttered, drawing the looks of all the people around him. "Go!" he repeated forcefully, "I will hold him back while the rest of you escape! Just get back to the ship!"

Looks of shock and disbelief appeared on all their faces. Erza took a small step forward, her lips pinching together in a tight line. "Natsu do you seriously expect to be able to hold it back?! It withstood all our attacks and more… There's no way that we can beat it." While she had started out shouting, her voice had grown more somber by the time she finished.

The boy shook his head slightly as his entire body burst into flames, doing his best to ignore the searing pain erupting all over his body. "I'll find a way." he muttered, staring at the girl before him. "And did you forget my promise? I promised that I would defeat anything that made you cry." As he finished, Erza gasped slightly, raising one hand to cover her mouth. Natsu turned to look at the approaching dragon one last time before looking back once more. "Now Go!" he roared.

Erza stared at him for a moment longer before giving him a slight nod. "Come on." she started, turning back to the others. "Let's not let this go to waste. Everyone get back to the ship!" Most of the members quickly followed Erza's command, offering Natsu one last thankful look before starting to run, every one praying to make it back in time.

Gildarts, for one, looked at the boy on fire in front of him. The older man sent a quick glance down at the sleeping man in his arms before forcing himself to turn away. "Be safe, Natsu. That thing is unlike anything you've fought before." Pausing for a moment, he continued, "I will take the master to the ship and then come back. Hold it off until then." With this, he started running, leaving only a handful of people behind. The first being Gajeel and Levy, with the former leaning heavily on the smaller girl, barely able to stand due to the injuries he sustained earlier. He grunted softly as she shifted below him.

Turning away, Levy muttered a quick prayer as Gajeel kept his eyes on Natsu. "Don't die on us, Salamander." he spoke, before turning and limping away, rushing back to the ship. Natsu glanced back at the dragon that was circling above, seemingly taunting them by letting his friends finish their goodbyes. He growled slightly and looked back down to the rest of them.

Lucy was crying, with a few tears slipping down her cheeks. She took one last look at Natsu before turning and running past Laxus. Natsu met Gray's gaze and they held each other's gaze for a few moments. Eventually, Gray broke away and sent a quick nod in his direction before running away after Lucy, rushing past the youngest member of their team. Wendy stood by the side, hugging Charla to her chest tightly. "I can stay, Natsu-san!" she yelled, causing Natsu's lips to curve up into a small smile. "I can heal you, and I'm a dragon slayer too!"

Natsu stared down at her for a moment, before letting out quiet chuckle. "Don't worry, Wendy. Do me a favor and get back to the ship. Once I get back I'm going to need you to heal me." As he finished, he took a small step forward and rustled her hair lightly.

The small girl shook her head slightly and looked up at the mage in front of her. "Okay." she said softly, her lips quivering slightly."Once you get back, I will heal you." She gripped the small exceed in her arms even tighter before turning away. When she noticed a small figure staring at Natsu with tears in his eyes, she paused. "Come on, Happy. You have to get back to the ship too."

Picking Happy up, she had only taken a few steps before she was interrupted by the last figure left the clearing. Laxus stood watching Natsu with an unreadable expression in his eyes. The blond had only spared the blue-haired girl a quick glance before reverting his gaze to the fire mage.

Wincing as he rolled one of his bandaged shoulders, he spoke, "Don't expect any heartwarming words from me." At his words, Natsu let out another small chuckle. "Just don't get yourself killed."

At those words, the light smile that Natsu had been adorning slowly morphed into a somber expression. He answered the lightning mage with a small nod before calling out to him, "Mind giving me a quick meal?"

With a smirk adorning his face, Laxus summoned the remnants of his magic and flung a bolt of lightning in Natsu's direction. Feeling his chest tighten in pain, he let out a few labored breaths as he watched Natsu consume the magic. After receiving a quick thanks from the fire mage, he turned and began to limp away, waving a hand towards Wendy to get her moving.

As she watched Laxus continue into the forest, her arms tightened around the two Exceeds she held against her chest. Happy had tears pouring from his eyes as he watched Natsu stand alone in the forest, while Charla stared at her fellow Exceed in sadness. After staying still for to long, Wendy felt Charla tug lightly on her dress. And when she glanced down, Charla only gave her a short nod as she pointed into the forest with one paw.

Ignoring Happy's cries, Wendy started after the rest of the guild. She had only taken a few steps before she was brought to a halt by Natsu calling out to her. Turning her head to look back, her eyes widened at the small smile on his face. "I need you to make me a promise Wendy." he started, staring at the girl in front of him with dark, piercing eyes. While his slight smile was reassuring, his eyes were filled with emotion, making her words get caught in her throat. She nodded slightly, a small amount of dread starting to build up within her.

"I need you to promise me that you'll get stronger. Even though you are already one of the strongest I know, I need you to promise that you'll protect Fairy Tail for me." As Natsu finished, he choked up and turned away, wiping a hand across his cheek. But besides that, he said nothing. With flames covering his body, he faced the dragon as he awaited an answer from the young dragon slayer. And after a moment, he heard her speak.

"O-Okay." she started, her lips trembling. And looking back at her out of the corner of his eye, he knew that she was close to just breaking down right there. "I promise. I promise to get stronger so that I can protect Fairy Tail just like you!" As soon as she finished, she turned and ran, making her way to the rest of the guild.

As Natsu had heard those words a small, grim smile had appeared on his face. He knew exactly how this battle would turn out, and he was just glad that he would be able to save his family. Slowly, he turned and looked back up at the beast above him. It continued to fly in that circle, staring down at the lone mage below.

Clenching his fists, determination shown in Natsu's eyes. There was no way he would allow this dragon to take him down without a fight. He was Natsu Dragneel! The son of Igneel! And he would protect his family with all his might.

Without waiting another moment, Natsu jumped up and let loose a pillar of flames from his mouth. "Fire Dragon's Roar!" he bellowed. Watching the attack get closer, Acnologia did nothing more than shrug the attack aside. With a single flap of its wings, the beast soared down, raising its claw to strike the teen down. The roar the dragon released rattled Natsu's bones once more. He had never faced anything near the power as this dragon. As he waited for the dragon to get closer, he felt the familiar tug in his gut as lightning crackled around the fire covering his hands, causing sparks to fly around the air.

As the dragon finally reached Natsu, it struck at the teen with surprising speed. For a creature of this size, he had never seen anything move that fast. Quickly brushing that thought aside, he raised his hand and blocked the gigantic claw with his own fist. "Lightning Fire Dragon's Iron Fist!" For a split second Natsu held the creature back, but Acnologia quickly let out another roar and pushed even harder, breaking through Natsu's spell.

The flames around the pink-haired boy dissipated as he was sent flying back, crashing through multiple trees before rolling harshly to a stop. Without a moment to spare, Natsu shot back up trying to ignore the pain erupting in his chest and quickly dodged another swipe from the dragon. Seeing how easily the creature had pushed through his spell, a sense that he had never felt before started to arise within him.

Hopelessness. During the S-Class trials, Gildarts had finally helped him understand what it meant to fear. And while he knew from the start that he feared this dragon, this foreign feeling was something he had never experienced before. Not when he had fought Jellal, Zero, or even Laxus. During those fights he never lost hope. He always pushed through so that he could protect his family. But standing here now, before the self-proclaimed King of the Dragons, he felt hopeless.

Natsu grimaced as he let out a low growl. He wouldn't let those thoughts stop him. He would fight until the end and make it back to the rest of the guild. Taking a breath, he covered his entire body in flames once more. Crouching down, he readied himself before launching himself at the dragon, winding his fist back. A roar escaped his lips as he struck, aiming towards the dragon's side.

The dragon had immediately noticed the approaching and had turned to stop him, but with an extra burst of speed, the boy was too fast. "Lightning-Fire Dragon's Iron Fist!" He screamed as his fist slammed into Acnologia's side. Flames quickly engulfed the spot, which was soon followed by a powerful bolt of lightning. Acnologia let loose an even louder roar before slamming its claw down onto the boy, effectively ending the attack.

Natsu's eyes widened as he noticed the claw descending towards him, but still recovering from his attack, he didn't have enough time to get out of the way. He let out a scream of pain as he was crushed against the ground. When the dragon lifted its claw, he wasted no time in pushing himself back to his feet and stumbling away as quick as possible. Spitting out some of the blood that had pooled in his mouth, he raised one hand and tentatively touched his forehead. Wincing, he slowly brought his hand back down to see his fingers covered in blood.

Facing the dragon once more, he crouched down into a low stance. He anticipated another attack from the dragon, but when nothing happened after a few moments, Natsu took a few steps back. The dragon had its head curved as far back as it could go, and it was staring intently at the side of its body. Natsu followed the dragon's gaze and smirked when he noticed what the creature had been looking at. On the side of its body, one of the large pitch-black scales had been cracked. A long-jagged line ran from the top of the scale down to the bottom, with the two halves spread slightly apart.

Natsu almost couldn't believe it. This creature had withstood all the guilds attacks, but he had somehow managed to wound the creature himself. For the first time in this fight, he felt that sense of hopelessness dissipate within him. As Acnologia turned back towards him, he got back into his fighting stance, ready for the attack.

But none came. The dragon just stared at the teen with rage burning in its eyes. And standing just a little way from the creature, Natsu felt like a pebble compared to it. If he wasn't so paralyzed with fear, he was sure that his legs would be trembling. The pressure that the dragon was emitting made him just want to crumble to the ground, and he wasn't sure how much longer he would be able to resist doing just that.

Acnologia let out a viscous roar. The force of it was so powerful that Natsu was blown back a few meters but managed to keep himself upright. Without sparing the teen a moment to recover, the dragon took off into the air and soared into the sky. When it was high enough to see all around the island, it turned and looked back down at its enemy. It released one more powerful roar as a bright light started to grow within its mouth.

Seeing the attack building within the dragon's mouth, Natsu readied himself. His body erupted into flames and sparks once more. He never took his eyes away from the dragon, and while he had thought of running, the odds of him making it to safety were slim to none. And so, if he couldn't make it back, he would do as much damage as possible before going out.

Natsu was momentarily blinded as the dragon finally launched his attack. He had never seen a spell this powerful before and braced himself as he watched the attack get closer. Taking in a deep breath, he started preparing his own counter attack. "Lightning-Fire Dragon's Roar!" He roared as he released one of his most powerful spells. The attack from the dragon dwarfed the roar from the dragon slayer, but that didn't stop the mage.

A small explosion erupted when the two attacks collided, and as the smoke it revealed that Natsu was holding back the dragon's spell. Refusing to give in, Natsu pushed even more power into the spell, but it was futile. With the dragon slayer already being wounded from the fight against Grimoire Heart the attack quickly became too much for him to handle. With one final roar, the dragon doubled the strength of his attack, easily pushing through the teen's spell.

As Natsu felt the last of his magic dissipate, he could do nothing but watch as the attack grew close. To him, it seemed as if time was moving in slow motion. He couldn't help but think about how Fairy Tail was going to be without him. It was where he had grown up, where he had finally found a family, and it was hard to believe that it was all over.

Refusing to look away, the last thing Natsu saw was a bright light.

Updated 8/26/2018

Ages are slightly altered. Natsu, Gray, Lucy, and the rest of the mages around their age are at or around 18 years old. Wendy is 12 at the start of the fic.

Make sure you leave a review and let me know what you think! The reviews always make my day! Next chapter should be out soon.