Starline is calm, theatrical, and sophisticated most of the time, exuding an arrogant sense of pride in his intellect and abilities. Rather formal in behavior, he often addressed others as "gentlemen". However, he is also ruthless, sinister, and cruel. Showing contempt for weakness, he possesses an incredible drive. Despite possessing a calm demeanor, his patience does have its limits. He also cares about his appearance a lot. He craves to control the world even if behind the scenes. Dr. Starline is an anthropomorphic platypus with white fur that covers most of his body. His bill is dark gray-colored and narrow with nostrils on the front, and he possessed red eyes with pale yellow sclera, black eyelids, and a thick tail that is similar to Knuckles. He also has three thick hair turfs on his head that were combed over the right side of his head. His front hair turf also possess a brownish-grey highlight. For attire, Starline wore a satin purple shirt with golden cufflinks, a red-violet vest, and orange pince-nez glasses. He also wore a webbed brown glove on his left hand with a gold insertion clip and golden-tipped fingertips. A darker brown ring could be seen on the palm of the glove. He also wore brown boots with golden buckles, red-violet soles, medium-high heels, the Multi-Tool Heel Spurs and upward-turned pointy toes and light red-violet socks underneath. For special occasions, Starline has worn different outfits: For cold weather, he wears a long dark purple hooded coat with fluffy pale purple trims. Occasionally, he only wore a red-violet T-shirt. Sometimes, he wears a red-violet bathing robe and slippers.