Heracles (ヘラクレス, Herakuresu) is a strange man that resides in the Greenstone forest in the Boin Archipelago. He is dressed in a beetle suit and uses a spear for combat. He saves Usopp twice, once from being attacked by a giant Hercules Beetle, and the other time from a Man Eating Plant. His attacks are apparently very fast.
He often adds "n" to the end of sentence (in Japanese). For example, He call Usopp (Usoppu ウソップ) to Usoppun (Usoppun ウソップン), or himself is Heraclesun (Herakuresun, ヘラクレスン). He also has a habit of repeatedly introducing himself.
His name, Heracles, comes from the Greek Hero Heracles, known as Hercules in Rome, or rather from the Hercules Beetle.
First Appearance: Chapter 524

Source: http://onepiece.wikia.com/wiki/Heracles