I. An Unexpected Guest
The Fairy Tail Guild was known for being the noisiest and most chaotic place in Fiore. But at this moment, it was the quietest, with the exception of the sound of Goku's chewing.
Erza had brought Goku to Magnolia, and the first order of business was to satiate the Saiyan's appetite. Goku was sitting at a table, devouring a mountain of pastries, roasted meat, and pitchers of milk, all paid for with gold confiscated from the Hyena Bandits. Natsu and Gray watched in awe.
"It's impossible!" Natsu shouted. "He just ate a week's supply for Gildarts!"
"It's just my normal appetite," Goku said, finishing an entire chicken in one bite.
Erza, meanwhile, sat next to him, her arms crossed and an expression of intense concentration. She wasn't irritated; she was analyzing.
"You didn't use magic, Goku. Not a single drop of Aether in the air. Your 'Ki' is a form of energy that resides entirely within your body. How do you control flight and striking power without a magic circle or an enchantment?" Erza asked, with the patience of a master.
Goku grinned. "Ah, well, flying is easy. You put Ki under your feet. The striking is just force and a lot of practice. Do you want me to teach you?"
"Silence," Erza said, without raising her voice. Her mind was grappling with a paradigm shift. The idea that power existed without magic was as strange as the sun rising in the west.
While Erza attempted to write on a scroll how to classify "Ki" as a new form of Lost Magic, Master Makarov, watching from the second floor, chuckled.
"Don't try to box it in, Erza. Some things simply are," Makarov advised, waving his tiny hand.
II. The Guardian's Challenge
Suddenly, a blaring alarm echoed through the guild. It wasn't the sound of Natsu and Gray fighting; it was the high-level security alarm, reserved for threats that could destroy the building.
"Master, an anomalous energy signature!" Mirajane shouted from the bar. "It's an unknown energy pattern, more intense than the Goliath from yesterday. It's heading straight for Magnolia!"
Erza rose instantly, her Flame Empress Armor already equipped in a scarlet flash.
"Goku, stay here! It's my job to protect the guild!"
"Wait, Erza! Maybe they want to play!" Goku said, sensing an energy signature distinct from the Corruption: a blend of refined magical energy with a cold, metallic edge, like a sword forged in the moon.
Outside, over Magnolia Square, people were screaming and running. Right in the center, where the sun's ray touched the clock tower statue, a portal shining with pure white light appeared.
Out of the portal, with a grace that defied physics, a woman landed. She wore sleek, futuristic armor with white and blue plates, and wielded a long, straight sword covered in runes of light. Her hair, the color of light chestnut, fell over her shoulders, and her eyes were clear and sharp, searching for something with cold determination.
It was Akiha, a Master Duelist and Guardian of the Rift from another realm, sent to investigate the massive Ki singularity that had disrupted the dimensional fabric.
"The source of the dimensional distortion is here," Akiha said, her voice a measured, clear tone with a slight foreign accent. She saw the crater left by the Goliath and then sensed the immense, though inactive, Ki signature coming from the Guild.
Seeing the unconscious Goliath, Akiha drew her sword and pointed it toward the Guild.
"The power that subdued that beast is a danger to all worlds! Surrender the source!" she demanded.
III. The Duel of Speed
Erza darted out of the guild, landing in front of Akiha with her sword raised.
"If you want the source, you'll have to go through me, intruder," Erza declared.
Akiha assessed her in an instant. "Elemental energy, re-equip, high speed. A worthy opponent. But not the source."
Before Erza could attack, Goku appeared between the two. He used the Instant Transmission.
"Stop, stop! She's my friend!" Goku said, scratching his head.
Akiha was stunned. The speed of that movement was impossible, transcending any known teleportation magic. Her training as a Master Duelist allowed her to react. She retracted her attack and focused on the man in the orange dogi.
"You... You are the anomaly. Your energy is pure, but your existence tears the fabric between worlds. I am Akiha, the Guardian, and I must test your intent," Akiha said. Her white sword glowed with a blinding light.
"Test? You want to fight? Awesome! But let's be quick, I'm getting hungry again!" Goku took a fighting stance, smiling.
The duel began and ended in a flash of light.
Akiha attacked with a flurry of thrusts that only Erza, with her mage eyes, could follow. It was the art of the Lightning Blade, a hundred cuts in one second, each aimed at vital points.
Goku simply dodged. He didn't use Ki, nor did he transform. He moved with a micro-speed that made Akiha's sword seem like a slow toy. Every thrust passed mere millimeters from his skin, but never touched him.
Akiha, realizing she hadn't landed a single hit, stopped, panting. The Saiyan stood, his arms lowered, smiling.
"What speed! You're really good!" Goku exclaimed, genuinely impressed.
IV. The Inexplicable Mastery
Akiha dropped her sword to the ground, the clank of metal echoing in the silenced square. She was trembling, not from fear, but from technical humiliation. In her world, she was considered the fastest and most precise swordswoman alive.
"Impossible... You didn't move. You didn't defend. You simply... weren't there when I attacked," Akiha whispered, her eyes wide.
Erza, who had witnessed the duel from the doorway, was equally astonished.
"What's wrong, Akiha? Aren't you going to fight anymore?" Goku asked.
Akiha looked up and saw the innocence on Goku's face, the lack of malice, the pure joy of fighting. She realized he wasn't a threat; he was a phenomenon.
She, the Guardian, suddenly felt lost.
"My mission was to neutralize the anomaly, but you... you are the purest phenomenon I have ever encountered," Akiha said, approaching him, her combat stance replaced by one of deep curiosity. "Your power is not evil. But it is so vast, it terrifies me."
Akiha knelt, a gesture of respect that shocked Erza.
"Goku. If you are the key to these portals, I must study you and protect you from those who seek to exploit you. Since I cannot defeat you, I offer you my service as your bodyguard and strategist."
Goku burst out laughing. "Sounds good to me! Three is better than two! Erza is the strong one, and you seem really smart. But first! Do you have anything to eat where you come from?"
Akiha smiled for the first time, a small, cautious smile. "In my realm, we have Class A ramen, Goku."
"I'm in!"
Erza watched as two of the most powerful people she had ever met made a pact over food. The Saiyan had not only entered her life, but was already gathering an entourage of strong women.