Vander Decken

Van der Decken is the captain of the "Flying Dutchman".

Cursed by God
According to legend, on a stormy day hundreds of years ago, Van der Decken suddenly became deranged and began killing off his crewmates by throwing them off the ship, which invoked the wrath of God. As punishment, he and his ship were forced to wander the seas forever.

As time passed, he eventually found another crew, which included Wadatsumi and Ankoro, hunting down coated ships that tried to descend to Fishman Island for their treasure.

Fishman Island Arc
Many years passed, he encounters the Straw Hat Pirates when his sea demon Wadatsumi stops an angler fish from eating the Thousand Sunny. Van der Decken then orders Wadatsumi to attack the Thousand Sunny so he can take their treasure. Unfortunately for him, the Kraken, having been tamed by Luffy, Zoro, and Sanji, intervenes and defeats the Umibouzu. Decken then yells at Wadatsumi to get up and retaliate, but is informed by one of his crewmates that the undersea volcano is about to erupt.

Trivia

 * In maritime folklore, Van der Decken's full name was Hendrik van der Decken. Whether this character shares the same name as his folklore counterpart is currently unknown.