Ubisoft's map of the area
The Gold Sea is a sea on Axeoth, and appears in the A Pirate's Daughter campaign in Heroes of Might and Magic IV.
Black Balfour was an infamous pirate that raided on the Gold Sea. He was killed in battle against Captain Swift, a rival pirate, and Tawni Balfour inherited his ship and crew. She realized that they weren't earning as much as they should, since they spent half their time fighting other pirates instead of merchant ships. A popular saying stated that "The Gold Sea is home to more pirates than fish". She decided to defeat the other pirates and conquer the Gold Sea.
First, she invaded the towns of Yanathrae and Frigiston, giving her control of the Strait of Storms. She then sailed south to the Strait of the Lost, battling the mermaids for control of the strait. She invaded the palace of the Mer-Queen and slew her in battle, taking control of the area.
With both these important passages under her control, Tawni could take down the other pirates that crowded the water. She crowned herself Queen of the Gold Sea, and set up a Pirate Kingdom that ruled the ocean.