Donald Moderate is a portly man with a long, hooked nose. He is missing his left hand and his right leg below the knee, replacing them with a metal claw and peg leg respectively. He wears dark purple trousers and suspenders over a white shirt with a frilly collar, as well as a blue bowtie, a pink jacket, and a tall and thin brown top hat with a bicorne-shaped rim.
Moderate is very excitable and very invested in the proceedings of the Pirates Festival and the race for Gol D. Roger's treasure. When his co-presenter Ann shows him up or interrupts him, he is shown to be rather depressed. Unlike Ann, he is a neutral commentator and has no favorite to win the treasure hunt. He was not complicit in Buena Festa and Douglas Bullet's plan and was unaware that the Pirates Festival was a sham, so he became very angry at Festa when he realized the host had led the Marines to the Expo.
Donald Moderate welcomed the attendants to the Pirates Festival alongside his co-presenter Ann, who he had demonstrate her Bijo Bijo no Mi powers. Moderate explained the ground rules of the event before presenting the hunt for Gol D. Roger's treasure on a floating island inside a bubble accessible through a Knock Up Stream. Moderate and Ann followed along the pirate free-for all excitedly, but were utterly shocked when a ship came up the Knock Up Stream and blew up the island. As the pirates ended up in the bay below, Moderate spotted a fleet of Marine ships approaching the island and realized that the Pirates Festival host, Buena Festa, had sold them out. Soon afterwards, he and Ann ran away. After Bullet's defeat, Donald is later seen arrested by the Marines.