His skin is blue and his brain is clearly visible. His lips are large and red and his nose is similar to SpongeBob's. His hair is orange like Bowie's was in real life in the mid-'70s and again in the mid-to-late '90s, and his left eye is colored green while the other one is blue.
He is usually polite towards others and has a positive attitude, until SpongeBob and Patrick pop the world's oldest bubble. This infuriates him and he orders the Atlanteans to seize them.
He also appears clumsy, because he fell down the stairs to the royal palace. He has had visitors before because he says that people do not usually stay with the tour that long. When he finds Plankton, "a talking speck," as a replacement for the bubble, he is no longer angry and is back to his old, friendly self.
Role in series
His antagonistic side is revealed when SpongeBob and Patrick pop the oldest bubble. Lord Royal Highness orders the other Atlanteans to go after SpongeBob and the rest of the crew. However, after Plankton replaces the bubble, he is friendly again to the main characters.
Lord Royal Highness's heterochromia iridium is a reference to a common misconception regarding his voice actor, David Bowie. It is often believed that Bowie had one blue eye and one green eye, as is present in his character's design, but in reality, Bowie suffered from anisocoria, the permanent dilation of the pupil, in his left eye; the condition was the result of a fistfight he got into when he was a teenager.