Sir Arthur (only called 'Arthur' in America) is a Star Warrior and the leader of Galaxy Soldier Army. He only appears in the anime Kirby: Right Back at Ya!. He has green skin, purple-blue eyes, and his armor is golden and star-shaped. He wields a gold and silver sword with a red gem on the hilt. Clearly, he is a high-ranking star warrior.
A Sir Arthur action figure
He, like Meta knight as an example, is one of the last surviving star warriors after nightmare destroyed most of them and him and the remaining crew help metaknight and kirby destroy nightmare.