I. An Emergency Breakfast
The morning after Akiha's arrival was strangely productive at Fairy Tail. Master Makarov, intrigued, had accepted the presence of Goku and Akiha under the strict supervision of Erza.
The trio gathered at a table. Goku devoured his thirtieth bowl of Class-A ramen (brought by Akiha), Erza frowned over a map of Fiore, and Akiha, with a small device from her realm, measured Goku's Ki readings.
"According to the data from my Dimensional Energy Analyzer, the Rift that brought you here, Goku, was not natural," Akiha explained, adjusting the glasses she had summoned with her technological magic.
"It wasn't an accident?" Goku asked, his mouth full.
"No. It was a forced attraction. Someone with power comparable or superior to yours, or technology that mimics that power, compelled you to come to this world. The Rift energy dissipated towards the ruins of Mount Hakobe, to the north."
Erza slammed her fist onto the table. "That's dangerous! If someone is trafficking dimensional energy, they could destroy Fiore."
"Agreed. I kept watch overnight. Natsu, Gray, even you, Erza, have Ki limits I can measure. But Goku..." Akiha looked at her device. "It is literally infinite. If Goku is a key, we must make sure no one knows."
"So, I can't fight at my maximum?" Goku asked, deflating.
"You can fight, but you must learn to contain your Ki. In your world, it is normal. Here, a Super Saiyan transformation could pulverize the continent," Akiha said seriously.
"What a challenge! I like it," Goku said, his smile returning.
"Good," Erza intervened with authority. "If the source is in Hakobe, we go there. Akiha, what's the plan?"
"The path is direct, but Mount Hakobe is cold and full of monsters. Given the intensity of the energy we are tracking, I suggest a stealth approach," Akiha said. "Erza, your Flame Empress Armor will be vital for the weather. Goku, you will follow us flying high above the clouds, concealing your Ki, and only descend if we send an emergency signal."
"Flying alone? Boring!" Goku complained.
"It's training, Goku. Controlling your Ki. If your Ki leaks, you will draw the wrong attention. Will you do it for me?" Akiha asked, looking at him with a rare tone of pleading.
Goku sighed. "Alright. I'll do it. For the Class-A ramen!"
II. The First Team
The journey to Mount Hakobe began that same afternoon. Erza and Akiha traveled on foot, moving with the combined speed of Erza's Re-quip magic and Akiha's optimized movement technique.
Goku flew far above them, concentrating on something he had never needed to do: reducing his power. It was like trying to reduce an ocean to a puddle.
"Come on, Ki, get small, get small..." Goku muttered, frowning.
From below, Akiha looked at her device. Goku's reading was now 0.001% of his maximum, yet still larger than the entire city.
"His control is monstrous, but his Ki is incomprehensible," Akiha murmured.
"Don't get distracted," Erza said. Her gaze was fixed on a point on the trail. "We have company."
The snow path stirred, and three Ice Yetis, large magical beasts with white fur and frost claws, jumped towards them. Erza Re-equipped into her Heaven's Wheel Armor.
"I'll handle them," Erza said, leaping with her multiple swords.
"No. I will," Akiha said.
Akiha didn't use Aether magic, only her refined internal energy from her own realm, channeled through her luminous sword. She was pure technique, not brute power. Her fighting style was elegant and terrifyingly efficient.
She stepped towards the central Yeti. As the monster attacked, Akiha executed a move called Phantom Slash. It was an illusion of speed. It looked like her sword had barely moved, but in reality, she had cut the beast's ice armor at twenty key points before the Yeti could even feel the pain.
The Yeti crumbled into inert pieces of ice.
"Impressive, Akiha," Erza said, noting the precision without magic.
"Brute force wastes energy, Erza. My goal is maximum efficiency. If we manage to pass unnoticed, we don't expose Goku," Akiha explained, wiping her blade clean.
III. The Nexus Cave
The trail of anomalous energy led the trio to a hidden cave on the peak of Mount Hakobe. The interior was warm, and in the center, the energy source pulsed.
It wasn't a creature. It was a gem, the size of a human fist, a dark, vibrant purple, embedded in the icy floor. The gem was pumping the same chaotic energy that had brought Goku to this world.
"That's the Rift energy!" Akiha said, approaching cautiously.
"It's horrible," Erza murmured. "What is it?"
"A battery. A dimensional nexus created to be a magnet, or an engine. Someone is using it to open portals and bring things... or people."
At that moment, the gem emitted a pulse. The cave trembled, and two new portals opened on the ceiling. Two figures fell out of them.
The first was a woman wrapped in a black and red robe, with short black hair and a look of intense frustration. She carried a giant scythe that struck the stone floor.
The second figure was a tall, muscular man in black plate armor, wielding a powerful broadsword.
"Finally! I thought the Rift had sent me to a dimension of bunnies," the woman with the scythe growled. It was Shinoa Hiiragi (from Seraph of the End), but her attire was that of a mercenary.
The man in the dark armor, with an aura of sinister power, looked at Goku, who had quickly descended upon feeling the new Ki.
"The Saiyan. You are the target. My mistress wants you alive. Surrender, or we will destroy this pathetic realm," the man said, his voice distorted by his mask.
"Wow! A fight again!" Goku grinned, forgetting the containment training. His Ki began to rise unconsciously, filling the cave with a pressure that made the purple gem vibrate dangerously.
"Goku, contain yourself! You'll destroy the cave!" Erza shouted, unsheathing an ice sword.
"That power! The Saiyan is the key!" exclaimed the woman with the scythe, pointing her weapon at Goku.
The mission had gone from stealth to confrontation in an instant. Goku's team already had its first enemy from another world.