King Nimbus is a Nimbus that has brown hair and a brown mustache. He also wears fancy blue clothes symbolzing his status as royalty.
During the events of the game, King Nimbus with his wife were kicked off their throne and locked into a room by Valentina. Using Dodo to disguise himself as Prince Mallow, Valentina attempted to take over Nimbus Land as it's new queen. Fortunately, the real Mallow shows up and he along with Mario] and the others defeat Valentina and Dodo and free King Nimbus and Queen Nimbus. King Nimbus then reunites with his son and shows him and the others the way to Barrel Volcano as thanks for freeing him and his wife. During the end credits, King Nimbus can be seen with his son Mallow who is happy to be appointed as prince.