Otto van Cooper is an ancestor of Sly's who was a genius mechanic and skilled fighter pilot. Due to his physical ineptitude, he used his talents to pull off heists, his machines facilitating his thievery. He kept some of his technical blueprints in the Thievius Raccoonus. The propeller blades of his biplane were shaped like the trademark Cooper hook. His section of the Thievius Raccoonus was stolen by the Fiendish Five's demolitions expert, the Panda King.