Fish-Man Island, outside Ryugu Palace.
The Flame Emperor lay anchored behind a secluded coral reef. Its bubble membrane had been disguised in the colors of ordinary reef rock, and every Glow Dial aboard had been switched off. The entire ship seemed to blend into the seafloor landscape.
"According to the map Hack provided, Ryugu Palace has four entrances: the main gate is heavily guarded, the eastern entrance is for nobles, the western entrance is for transporting supplies, and the southern side..." Robin pointed to a mark on the nautical chart. "There's an 'emergency passage' here. Queen Otohime built it during her lifetime to evacuate the royal family in a crisis. Only the king and the three princes know about it."
"Hody controls Ryugu Palace now. The passage might have been discovered too." Ace frowned.
"No." Hack-the Fish-Man warrior who had escaped from Fish-Man Island-shook his head. "Even most of the ministers don't know it exists. Queen Otohime built it in utmost secrecy, using ancient Fish-Man Race technology. Only someone of royal blood can open it using their Lineage Factor."
He looked at Lin Yan. "Lord Flame Emperor, that gold-and-red pendant you carry... I saw a similar design with Queen Otohime. She said it was a token of the Sun God Covenant, and its bearer could open any ancient Fish-Man Race ruins. Perhaps... it can open the passage too."
Lin Yan took out the pendant. In the deep sea, its light softened, but it still radiated warmth.
"Let's try it." He put away the chart. "Isuka, stay aboard with five others. Ace, Tashigi, Robin, Chopper, Hack, you're coming with me. If you hear nothing from us within three hours, withdraw immediately and wait at the Sea Forest."
"Yes!"
The six changed into special diving suits-Chopper had improved them using the Fish-Man Island Technical Blueprints. Equipped with miniature breathing apparatuses and propulsion systems, they allowed half an hour of unrestricted movement underwater.
They left the Flame Emperor and descended into deeper darkness.
The passage entrance lay beneath a massive coral rock at the base of Ryugu Palace. Covered in barnacles and seaweed, the rock looked utterly unremarkable. But Robin's Flower-Flower Fruit sensed a complex mechanical structure inside it.
Lin Yan pressed the pendant against the rock.
The pendant shone gold, and the mechanism within the rock began to operate-not with the sound of turning gears, but with an older kind of resonance, like singing. A design of an intertwined sun and trident appeared on the rock's surface. Then it slowly parted to either side, revealing an opening barely wide enough for one person.
"It really opened..." Hack said excitedly. "Everything Queen Otohime said was true! The Sun God's successor really would come to save Fish-Man Island!"
They entered one after another.
The passage was narrow, but luminous pearls embedded in the walls provided light. It climbed all the way up, evidently leading to Ryugu Palace's upper levels.
After about ten minutes, light appeared ahead-a concealed observation opening overlooking Ryugu Palace's main hall.
They drew closer to look.
The sight inside the main hall made their hearts sink.
The once magnificent hall was now a wreck. Precious coral decorations had been smashed, and pearl curtains torn down. The throne stood empty. In the center of the hall, a blue-skinned shark Fish-Man-Hody Jones-sat on a "temporary throne" made of Seastone, with King Neptune's crown beneath his foot.
Several key officers stood beside him: the hammerhead shark Fish-Man Dos, the kissing fish Fish-Man Zeo, and... a figure who made Hack's pupils contract.
"Vander Decken IX..." Hack gritted his teeth. "Captain of the Flying Pirates, and a Mark-Mark Fruit user. Why is he conspiring with Hody?"
Vander Decken was an ugly catfish Fish-Man. At that moment, he was reporting obsequiously to Hody:
"Lord Hody, the seal on the Hard-Shell Tower has weakened a little more. That girl Shirahoshi's power is awakening. At most, three more injections of the Energy Steroids Catalyst will let her fully control the Sea Kings!"
Hody grinned, exposing sharp teeth. "Excellent. Once we have Poseidon under our control, we'll destroy every human ship docked at Fish-Man Island, then attack Mary Geoise! Let those Celestial Dragons taste what it's like to be torn apart by Sea Kings!"
"But..." Dos hesitated. "Lord Hody, Queen Otohime taught us during her lifetime that we should live peacefully with humans..."
"Shut up!" Hody roared, sending Dos flying with a punch. "That stupid woman Otohime! It's because she prattled on about 'peace' all day that humans look down on the Fish-Man Race! Brother Arlong was right-only force can make humans afraid! Only slaughter can win respect!"
He stood and walked toward a statue in the center of the hall-it was a statue of Queen Otohime, now smashed beyond recognition.
"That hypocritical woman, spouting nonsense about how 'the Sun God will bring the dawn'..." Hody kicked the statue viciously. "And what happened? After she died, humans hunted merfolk even more ruthlessly! Our people in the Fish-Man District are still starving! But I-"
He pointed at himself. "I, Hody Jones, will lead the Fish-Man Race to true strength! With blood and fire, I'll build a nation of our own!"
Behind the observation opening, Hack's clenched fists cracked, and his tears mingled with the seawater.
Robin, however, narrowed her eyes.
"Something's wrong," she whispered. "Hody's rhetoric is extreme, but his actions... are far too organized. A coup, kidnapping the princess, researching the Energy Steroids Catalyst, even recruiting a lone pirate like Vander Decken. This doesn't seem like something a Fish-Man simply blinded by hatred could plan."
Lin Yan nodded. "Someone is guiding him from behind the scenes. And that person... knows a great deal about the secrets of the Ancient Weapons."
Just then, Vander Decken said something else that made all their pupils contract:
"Lord Hody, that 'sponsor' sent another shipment of supplies, including the latest Seastone shackles and the Energy Steroids Improvement Formula. He said... once it's done, he wants 'one tear' from Princess Shirahoshi as payment."
"A tear?" Hody frowned. "What use is that?"
"He said it was 'research material.'" Vander Decken shrugged. "He didn't give any details. But the supplies are real, and so is the formula. Who cares?"
The sponsor.
The mastermind behind the scenes.
Lin Yan and Robin exchanged a glance, each seeing the gravity in the other's eyes.
Anyone who could provide Seastone and the Energy Steroids Improvement Formula was certainly no ordinary force. The Navy? The World Government? Or... some "king" hidden in the shadows?
"We rescue Shirahoshi first," Lin Yan decided. "Where's the Hard-Shell Tower?"
"In the deepest part of Ryugu Palace. We need to cross three guarded corridors." Hack pointed toward the other side of the passage. "This way will let us avoid most of the guards."
The six pressed on.
The passage was a maze of branching paths. But with Hack leading them, they soon reached the area outside the Hard-Shell Tower.
It was a fortress built entirely of Seastone mixed with coral. The tower had no windows, only a heavy alloy door. Complex sealing runes covered the door-derived from the same source as the runes at Fish-Man Island's entrance, all ancient Fish-Man Race technology.
"Princess Shirahoshi is inside." Hack's voice trembled. "But the seal on the door... only royal blood or a Sun God token can open it. We..."
Lin Yan took out the pendant again.
But this time, it did not respond.
"What's going on?" Ace asked.
Robin studied the runes carefully. "These runes... have been altered. A Lineage Lock has been layered over the original Sun God Seal. It can only be opened with a specific bloodline. And-"
She pointed to a faint mark at the edge of the runes. "There are hidden runes here written with the Energy Steroids Catalyst. They function as an 'alarm.' If we force the door open or try to open it the wrong way, the alarm will immediately spread throughout Ryugu Palace."
A trap.
Hody had anticipated that someone would come to rescue Shirahoshi.
"Then what do we do?" Tashigi tightened her grip on Shigure. "Force our way through?"
"No." Lin Yan shook his head. "That would alert them. We..."
Before he could finish, singing suddenly drifted out from inside the Hard-Shell Tower.
It was a song beyond description-ethereal, sorrowful, pure, as though it held the longing of the entire ocean. It pierced the thick Seastone door and echoed through the corridor, making every soul tremble.
Princess Shirahoshi was singing.
She was using her song... to call for help.
More astonishingly, as the song rose, the pendant in Lin Yan's hand suddenly blazed with unprecedented light!
Within the golden light, a line of Ancient Script appeared:
[When the mermaid princess's tears become song, successor of the sun, please warm her heart with your flames. -Nika, left during the Void Century]
At the same time, the system notification sounded:
[Resonance detected with the Ancient Weapon Poseidon] [Special quest activated: Rescue the mermaid princess Shirahoshi] [Quest rewards: Ocean Shard clue, Sun God Nika legacy unlock (5/5), Bond System advancement]
Lin Yan looked at the pendant in his hand, then at the tightly shut door.
He understood.
He was not supposed to "open the door."
He was supposed to make the door "open on its own."
"Everyone, stand back," he said.
Then he walked up to the door, pressed the pendant against it, and closed his eyes.
"Sun God Nika: False Form-"
"Voice of Dawn."
Crimson-gold flames surged from his body.
But this time, they were neither an attack nor a defense. They were "resonance."
The flames became countless points of light, each carrying a musical note-using the Genesis Furnace, Lin Yan converted flame energy into Sonic Energy, recreating a melody on the same frequency as Shirahoshi's song.
The two songs intertwined on either side of the door.
The golden song of flame and the ethereal song of a mermaid.
Like a conversation spanning eight hundred years.
The runes on the door began to light up and release, layer by layer.
They were not broken by force, but awakened by "resonance."
The seal left by the ancient Fish-Man Race had always been intended to await "the resonance of the Sun God and Poseidon." When the two songs met, the seal deactivated on its own.
Rumble-
The heavy Seastone door slowly swung inward.
Beyond it lay an enormous circular hall.
The center of the hall held no water, only air. A giant mermaid more than ten meters long lay curled on a bed covered in soft seaweed, singing quietly.
She had long pink hair and delicate features, and her lower body was a fish tail shimmering with a pearly luster. Even with her eyes closed, one could sense her pure, gentle presence, which nevertheless held terrifying power.
The princess of Fish-Man Island, the current bearer of the Ancient Weapon Poseidon-
Shirahoshi slowly opened her eyes.
They were blue, like the purest ocean.
She looked toward the people at the entrance, her gaze finally settling on Lin Yan.
Tears slipped from the corners of her eyes.
"You've finally come..."
"Lord Sun God."
Before you continue