Captain Syrup is the leader of the Brown Sugar Pirates (later the Black Sugar Pirates) and rival to Wario. In the original Wario Land, she stole a giant statue of the Princess and built Syrup Castle around it on Kitchen Island. By destroying her castle in an attempt to gain revenge on Wario for defeating her genie in battle, she revealed the statue to him. In Wario Land II, she and her Pirate Gooms snuck into Wario's castle by nightfall and robbed him of all his treasure. Wario then chased she and her henchmen across the island and back to their own castle, which had been rebuilt by then.
After that, Captain Syrup had a long absence from the world of video games. She finally reappeared in Wario Land: Shake It!, when she introduced Wario to the Shake Dimension and the plight of its inhabitants. She then operated an in-game store on her new ship "The Sweet Stuff" called "The Pirate Shop" which sold Wario maps to new levels and extensions to his health meter.