Elbaf

The coastline of Elbaf was rougher than Natsu had expected. The rocks rose from the sea, each the size of a small hill, their surfaces covered with deep grooves carved by weathering and waves.

The sand on the shore wasn't fine sand, but gravel that crunched underfoot.

In the distant forest, the tree trunks were ridiculously thick, the smallest being several meters in diameter, with branches stretching out horizontally for dozens of meters, completely blocking out the sky.

Standing in this world of giant scale, Natsu's two-meter height seemed out of place.

The Yaoyu and Yakumi followed him half a step behind, his gray-white uniform fluttering in the sea breeze.

Yaoyu glanced at the surrounding reefs and forest, and muttered under his breath, "This place is quite big."

"What's the use of being big?" Yakumi said, "They don't even have a King-Class weapon."

Natsu didn't reply, and started walking deeper into the island.

The Giant Tribe warriors quickly surrounded them.

Dozens of giants emerged from behind the rocks and bushes, clutching stone axes, iron spears, and enormous spiked clubs, their heights generally exceeding ten meters.

The leading giant shouted something, Natsu didn't understand.

Yaoyu took a step forward, and his Mangekyō Sharingan spun around in its socket.

The dozens of giant warriors froze simultaneously, their stone axes and iron spears slipping from their hands and crashing to the ground with a series of dull thuds.

The Yakumi bypassed the flanks, using Genjutsu to freeze several giants who were trying to flank from behind.

"Don't hurt them," Natsu said.

Yaoyu withdrew his pupil power, and one after another, the giant warriors collapsed to the ground, their eyes unfocused.

Natsu walked through them and continued walking in.

Outside the Western Village Warrior Village in the Sun World, Elder Jarul was already waiting with his men.

The old giant leaned on a bone staff taller than himself; his hair and beard were all white, but his back was still straight.

He watched Natsu walk over, and his bone staff paused on the ground.

"The head of the Uchiha Clan," Jarul's voice was deep, spoken slowly but clearly in the common human language, "What brings you to Elbaf?"

"Pass on the message," Natsu said, "The Uchiha Clan's rules must be observed everywhere on this sea. The Giant Tribe are no exception. Submit, or die."

Jarul remained silent for a moment. "The Giant Tribe has never participated in conflicts between humans since ancient times. We remain neutral."

"The word 'neutrality' is obsolete from today onwards," Natsu said. "Give me an answer within half a day, before dark."

Jarul's bone staff paused again.

The Elder behind him all paled, but no one made a move. They could see the dozens of warriors outside who had been knocked down by Yaoyu still lying paralyzed.

The old giant finally nodded, turned around, and led the Elder into the village.

He paused halfway there, turned his head, and said, "Uchiha Clan Head, the Giant Tribe have our pride. If we submit, we hope to preserve our customs and traditions."

Natsu glanced at him.

"Customs and traditions can be preserved. Laws and regulations must be followed according to the Uchiha Clan's rules. You can discuss it yourselves."

Jarul went inside.

Natsu did not wait.

He turned his head and, amidst the Yaoyu and Yakumi of the medicine, said, "Keep an eye on this place. I'm going to check out the Underworld."

Yaoyu paused for a moment.

"The Underworld?"

"That old man's tone was off when he mentioned Loki." Natsu had already turned and walked towards the Root of the Treasure Tree Adam. "I'm going to check on the prince who's been locked up."

The Underworld is much colder than the Sun World.

The air was filled with the smell of frozen earth and rust, and the ground beneath our feet had changed from gravel to permafrost that never thaws, feeling hard as a rock.

Treasure Tree Adam's roots surged up from the ground, as thick as mountains, their intricate network dominating the entire space.

On one of the thickest roots, a person was locked.

Loki sat there, even larger than Natsu had expected.

His bloodline Ancient Giant Tribe made him far larger than ordinary giants; even when he was curled up, his shoulders and back reached the lower edge of his roots.

Her dark red hair was disheveled and loose, with a pair of jet-black curved horns extending from either side of her headdress.

Seastone chains wrapped around his body, from his shoulders to his wrists to his ankles, the ends of which were driven into the roots of the Adam Tree.

Those chains not only bound his body— the Seastone suppressed the Devil Fruits power within him, preventing him from transforming or exerting any strength.

Beside him lay a huge hammer, its body dark and still, as if it were asleep.

That's Iron Thunder.

A living hammer that ate the Ice Squirrel Devil Fruit of the Mythical Zoan, with old cloth wrapped around its handle, the will of the Ice Squirrel dormant within.

Loki raised his head.

Those eyes fell on Natsu, heavy with the dry, resentful energy unique to someone who had been imprisoned for six years.

"Human," his voice echoed between the stone walls of the Underworld, "You've come to the wrong place. This isn't a place for the living."

"Uchiha Natsu." Natsu stood several dozen meters away from him, looking up at him. "Here, I'll give you a choice."

Loki paused for a moment, then grinned. It was a rough smile, his teeth uneven. "Uchiha Natsu. The guards outside have been talking about you."

"They say you wiped out the Navy, killed all the Celestial Dragons, and erased the World Government from the map."

He tilted his head slightly. "Then you should know who I am."

"Loki, the prince of Elbaf, the one who killed his own father. He ate Nidhogg."

Loki's brow twitched.

He neither denied patricide nor the fact that the Devil Fruit.

"Yes, patricide. Then I was tied up here with Seastone chains by a red-haired coward, and I've been bound for six years." He moved his wrist, the chains rattling. "Are you here to kill me, or to release me?"

"Neither," Natsu said. "I came to ask you if you want to come out."

Loki's brow twitched again.

"Come out? This chain is made of Seastone. You can't cut it."

Natsu did not answer.

He took a step forward, raised his right hand, palm down, and the Mangekyō Sharingan quietly rotated once in its socket.

The power of Indra's Eye surged from its pupils, condensing into a dark purple membrane in its palm.

He snapped his fingers.

A very thin, dark purple Chakra Threads shot out from his fingertip, slicing through the middle of the nearest Seastone chain.

The chain snapped at the cut, sending debris flying everywhere.

The second one, the third one, the fourth one.

Natsu flicked his fingers seven or eight times, and the Seastone chains binding Loki's limbs and torso broke one by one, falling onto the frozen ground with a clatter.

Loki was stunned.

He looked down at the broken chain still on his wrist, then looked up at Natsu, his expression shifting from stunned to something extremely complex.

As soon as the Seastone broke, the demonic power that had been suppressed within him for six years surged up immediately, and dark red scales flashed beneath his skin.

"Seastone... you just broke it like that?"

"Seastone is just a harder rock to me," Natsu said, withdrawing her hand. "I'm not a power user."

Loki remained silent for a few moments.

Then he stood up.

The bodies of the ancient giants stretched out among the roots of the Underworld, their heads almost touching the bottom edge of the roots of the Adam Tree.

He cracked his wrists, and his knuckles popped and popped.

The hammer— Iron Thunder —moved slightly at his feet, a faint icy blue halo rose from its surface, and then it floated up and landed in Loki's palm.

"Fine." Loki gripped Iron Thunder tightly, looking down at Natsu. "Let me out. I owe you a favor. Tell me, what do you want me to do?"

"Let's fight," Natsu said.

Loki's hammer stopped in mid-air.

"What?"

"I said, let's fight." Natsu put her hands behind her back, her tone flat. "You've been locked up for six years, you've been holding back a lot of anger. I'm letting you out, you need to find somewhere to vent. Vent it on me. If you win, you go your way. If I win, you come with me."

Loki stared at him for several breaths.

Then he laughed, a much bigger laugh than before, revealing all his teeth.

"You're interesting. Fine. If I kill you, don't blame me."

He lifted the Iron Thunder up.

The lightning crackled around the hammer, and the icy blue sparks exploded in the darkness of the Underworld, illuminating the entire root system.

Loki didn't waste any words and immediately brought down his hammer.

The Iron Thunder, carrying lightning and cold air, hammered the frozen earth beneath their feet, causing it to crack inch by inch.

Natsu sidestepped the hammer's edge, and the Iron Thunder slammed into the Adam Tree behind him. Frost spread outwards from the point of impact, freezing a large area of the roots.

"The Primordial World." Loki uttered a low shout, and the chilling aura emanating from the Iron Thunder surged.

The Ice Squirrel's power surged from the hammer, spreading freezing mist along the ground, causing even the air to condense into ice crystals wherever it passed.

Natsu didn't give him a second chance.

He flashed to Loki's shoulder height, his right hand reaching out and gripping Loki's hammer-wielding wrist.

Loki struggled, but couldn't break free.

He looked down at the hand gripping his wrist, his eyes widening.

"You--"

"You're quite strong," Natsu said, "But it's not enough."

He released his grip, took a half-step back, and the power of his Mangekyō Sharingan surged forth, condensing into a dark purple light membrane in his palm.

Loki held the Iron Thunder in front of him, lightning crackling around its shaft, and frost erupting from its surface.

He roared and charged forward, the Iron Thunder carrying the dual impact of lightning and ice, slamming into Natsu's front.

Conqueror's Haki emanated from his fist, dark red arcs of electricity enveloping the hammer, its power causing the roots of the surrounding Adam Tree to tremble.

Natsu raised his hand and caught the hammer in his palm. The lightning passed through his arm, but was silently neutralized by the Chakra fused from the Sage Body and the Indra's Eye.

Frost condensed in his palm, then melted under the warmth of his palm.

Iron Thunder stopped in front of his palm, unable to push it in.

Loki pressed down with all his might, his arm muscles bulging with veins, but he just couldn't push the hammer down.

"That's it?" Natsu asked.