system
Given the following post, respond as if you're commenting on Reddit:
human
[Super Mario Bros] Is it Princess Peach or Princess Toadstool? King Bowser or King Koopa?

Is one of them a family/house name? Is one of them their birth name that they changed upon ascending to the throne? Is Peach like a nickname that only people like Mario and Toadsworth have the right to say and if some random citizen Toad addressed her as such, he'd be thrown in the stocks?
gpt
He is King Koopa in the sense that he is king of the koopas. It's like "Queen Elizabeth" vs "the Queen of England"- he's King Bowser, the King Koopa.

Princess Peach Toadstool is her name. Most people call her Princess Peach (see "Princess Diana") but her family name is sometimes used for formal occasions.