Ep 31. The Worst Man in the Eastern Seas! Fishman Pirate Arlong!

As the fourth member of their crew, Sanji, joins up with Monkey D. Luffy and his gang, the Straw Hat Pirates continue their journey ahead. The crew reaches the Cocoyasi Village, where they quickly realize that the village is under the fierce grip of an infamous Fishman Pirate named Arlong, who is notorious for his forceful rule and ruthless behavior. Arlong's crew and his Fishman powers make him a formidable enemy, and it is rumored that he has a secret plan to take over the entire East Blue.

Upon arriving in the village, the Straw Hats meet Nami, a skilled navigator, and a former member of Arlong's crew. Nami initially appears friendly and helpful, but soon Luffy and the others realize that she is secretly working with Arlong to carry out his grand plan. Nami is forced to work for Arlong, stealing treasure and goods for him, in exchange for his crew's assistance in rebuilding her hometown.

Luffy and Sanji soon learn of Arlong's iron rule, which includes a mandatory "tribute" for the residents of Cocoyasi Village, and how he has been exacting payment for the past eight years, causing the village to suffer greatly. The crew decides to take up the cause of the villagers and fights against Arlong's crew. They soon realize that defeating Arlong himself is easier said than done, as he possesses incredible strength, speed, and regenerative abilities due to his Fishman heritage.

Despite the challenges, Luffy and his crew are determined to succeed. The battle becomes even more dangerous as a powerful Navy captain arrives on the scene, driven by his own agenda. In the midst of the chaos, Luffy and his friends must find a way to defeat Arlong and his cohorts, rescue Nami from his clutches, and put an end to his terrorizing reign of the East Blue once and for all.

The episode is filled with intense action and suspense as the Straw Hat Pirates fight against Arlong's crew to liberate Cocoyasi Village from their oppression, and Nami's true alliance is put to the test. Viewers are sure to be captivated by the incredible animation, well-developed characters, and engrossing plot twists that make One Piece one of the most beloved anime series of all time. The Worst Man in the Eastern Seas! Fishman Pirate Arlong! is a must-watch episode for fans of the series and all anime lovers alike.