Surume is a giant Kraken that was threatened into serving Hody Jones when he threatened his bothers, but befriended by Luffy.
Surume was originally only known as the Kraken that lived in the seas of the Northern Poles. He was approached by the New Fish-Man Pirates leader, Hody Jones; and he threatened to harm his brothers if he didn't cooperate with him. For several years, Kraken watched guard at the Grand Line downwelling current to the entrance that leads to Fish-Man Island.
Surume is a supporting character in the One Piece series that was created by Eiichiro Oda. The series first began serialization in Shueisha's Weekly Shōnen Jump on August 4, 1997. His first appearance was in the later Fish-Man island Arc that began in Volume 61.
His first appearance was in One Piece Volume 62 CH. 604 "To the Deep Sea", and his first anime appearance was in One Piece - Episode 524 "Deadly Combat Under the Sea! The Demon of the Ocean Strikes!". There is no voice actor listed for this character since he has no spoken lines.
The name Luffy gave the Kraken come from the name of a Japanese snack made from dried squid (鯣, surume)
While still crushing various ships on Hody's orders at the downwelling current, the Kraken came across the Straw Hat Pirates. His attacks on their ship were blocked, Sanji kicked and burned one of his arms, the sword fighter, Zoro, sliced off one of his other arms, and their leader Luffy knocked him out with a single punch. He fell down the current with Luffy, Zoro, and Sanji. Kraken was tamed by the power of Luffy and followed his orders, and he was named Surume. He defended Luffy's crew and beat up Wadatsumi of the Flying Pirates from destroying the Straw Hat's ship. Surume carried their ship as they ran from the underwater volcano then reached Fish-Man Island. Surume was worried when they were cut off by New Fish-Man Pirates members outside the island, and the Straw hats launched off in without him.
Surume was summoned by Hody Jones to help him in his battle to take over the island and kill Princess Shirahoshi, but Luffy was leading the fight against Hody. He asked Surume to protect the princess. He was happy to until Hody openly threatened to attack his brothers in the north and sell them. Surume was worried until Luffy asked him for his trust to let him help protect his brothers too, since they were friends. Surume later helped in the battle, but was knocked unconscious by a drug enhanced Wadatsumi.
When he woke up, Luffy had defeated the Hody and protected the island. Surume helped the royal family by taking Wadatsumi, who was too large for any prison; and carried him away.