Chapter 510: Exploring the Mysterious Island, Seal the Ruins and Challenge the Unknown

Sanji used the Devil's Wind Kick to launch a flaming kick: "Devil's Wind Kick? Mutton SHOT!" His attack loosened the tentacles a little. Nami summoned lightning with the weather stick and struck the tentacles. Usopp used the newly invented "cutting bomb" and fired it at the tentacles. The bomb exploded and could cut objects.

Chopper transforms into a giant form and attacks the tentacles with his antlers. Robin uses the power of the Hana-Hana no Mi to grow arms on the tentacles and tries to fight them. Franky attacks the tentacles with laser beams, while Brook uses the sound of the soul to interfere with the tentacles' movements.

In the fierce battle, they found that these tentacles seemed to be controlled by some huge sea monster. In order to completely get rid of the danger, they must find the sea monster and defeat it.

Luffy and his companions followed the direction of the tentacles and dived into the seabed. On the seabed, they saw a huge octopus sea monster. The octopus sea monster had an extremely large body and its eyes flashed with a fierce light.

"That's the guy. Let's go together!" Luffy shouted. They rushed towards the octopus monster and started a thrilling underwater battle with the monster.

Luffy used his rubber arm to attack the sea monster's eyes: "Rubber? Bullet!" His attack made the sea monster struggle in pain. Zoro, Sanji and others also used their own special skills to attack the sea monster's body.

Nami used the weather stick to summon ice elements on the seabed, trying to freeze the sea monster's movements. Usopp used a special "depth-sea bomb" and threw it at the sea monster. The bomb exploded under the sea monster's body, generating a huge impact force.

Chopper transformed into a special underwater combat form and attacked the sea monster with his body strength. Robin used the power of the Hana-Hana Fruit to set up obstacles around the sea monster to restrict its movements. Franky used laser beams to attack the sea monster's vital parts, and Brook used the sound of the soul to interfere with the sea monster's nerves.

With everyone's joint efforts, the octopus sea monster was finally defeated. Its tentacles loosened the ship, and the whirlpool gradually disappeared. Luffy and others successfully escaped from danger and continued to sail on the sea.

They know that there are countless adventures and challenges waiting for them in this vast ocean, but they never back down, because they are the Straw Hat Pirates, a group of adventurers who pursue their dreams and move forward courageously.

After defeating the octopus sea monster, Luffy and his companions continued to sail on the sea. Not long after, they found an island shrouded in thick fog ahead. From time to time, strange lights flashed on the island, as if hiding countless secrets.

"Wow, that island looks mysterious. Maybe there are great adventures waiting for us!" Luffy shouted excitedly, his eyes full of anticipation. His friends were also infected by his enthusiasm and prepared to explore the island.

The boat approached the island, they lowered the boat and slowly sailed to the shore. As soon as they stepped onto the island, a mysterious atmosphere hit them. The surrounding trees were tall and dense, with branches and leaves intertwined, and the sunlight could only shine through the gaps to cast mottled light and shadows.

"Everyone, be careful. There's something wrong on this island." Robin warned, her eyes scanning the surroundings vigilantly. Everyone walked along a winding path, and suddenly heard a melodious flute sound. The flute sound was ethereal and ethereal, as if it had some kind of magic, which made people unconsciously want to get closer.

Luffy and the others walked in the direction of the flute sound, and soon saw an empty grassland, where a man in a white robe was sitting and playing the flute. His face was handsome and cold, and his eyes were deep, as if he could see through people's souls.

"Who are you? Why did you come to this mysterious island?" The man in white stopped playing and slowly asked. Luffy smiled and replied, "We are the Straw Hat Pirates. We saw this island while sailing on the sea and wanted to see if there was anything interesting."

The man in white frowned slightly: "This island is not an ordinary place, it hides ancient powers and dangerous secrets. You'd better leave as soon as possible." However, Luffy would not be scared by such words. He shouted: "We are not afraid of danger. We will uncover any secrets!"

Seeing that his persuasion was fruitless, the man in white sighed helplessly: "In that case, I will give you some hints. There are three mysterious ruins on this island, each of which seals a different power. But recently, a dark force is trying to break the seal and release the evil power. If you insist on exploring, be careful."

After Luffy and his companions thanked the man in white, they set out for the first ruins. On the way to find the ruins, they encountered some strange creatures. These creatures looked like monkeys, but their bodies were covered with thorns and their eyes flashed red. When they saw Luffy and his companions, they jumped down from the tree and attacked.

Luffy quickly stretched out his rubber arms and knocked away the approaching monkey monsters one by one: "Rubber? Whip!" Zoro brandished three swords, and the sword lights flashed in the woods: "Three Swords Style? Tornado!" His attack swept like a whirlwind, chopping down the monkey monsters one after another.

Sanji moved flexibly in the air with the Moon Step, and kicked out powerfully with his legs: "Devil's Wind Kick? Devil's Dance!" Nami summoned wind with the weather stick, blowing the thorny monkeys all over the place, and attacked them with lightning. Usopp took out the newly invented "sticky trap bullet" and fired it at the thorny monkeys. The trap bullet formed sticky glue on the ground, sticking many thorny monkeys to the ground and making them unable to move.

Chopper transforms into a fighting form and fights the thorny monkey monster with his antlers and fists. Robin uses the power of the Hana-Hana-no-fruit to grow arms on the tree, grabs the thorny monkey monster and throws it far away. Franky attacks the thorny monkey monster with laser beams, and Brook uses the sound of the soul to interfere with their actions.

After a battle, they successfully repelled the thorn monkey monster and continued to move forward. Finally, they found the first relic. The relic was an ancient stone tower with various mysterious runes and patterns engraved around it. The door of the stone tower was closed, and there was a circular groove on the door, which seemed to require some special items to open.

"What should we do? Where can we find something to open the door?" Usopp scratched his head in distress. Luffy looked around and suddenly saw a small cave not far away. He pointed at the cave and said, "Maybe there are clues inside, let's go and take a look!"

The group walked into the cave, which was dark and damp, with a pungent smell. Deep in the cave, they found a crystal ball emitting blue light. The crystal ball was suspended in the air, surrounded by a weak electric current.

"This crystal ball looks very unusual. Could it be the key to open the door to the ruins?" Robin guessed. Luffy stretched out his hand to grab the crystal ball. Just as his hand was about to touch the crystal ball, a large amount of black smoke suddenly gushed out of the cave. In the smoke, some ghostly figures appeared, and they pounced on Luffy and others with their fangs and claws.