Why are there Arthur in so many games? Lol, Million King Arthur, etc. So does this Arthur have a prototype?

Yes, arthur pendragon (also translated as King Arthur Panlong), known as King Arthur in history, was the legendary great king of medieval England. People's perceptual knowledge of him comes more from Celtic myths and legends and some medieval documents, and no one has set foot in King Arthur's real life. Legend has it that he is the leader of the Knights of the Round Table, an almost mythical legend, and is called "the king of the past and the future".