Who is King Lotharon and Queen Bella from The Princess Bride and what is their importance?

King Lotharon is King of Florin and Humperdinck's father. He is very old and no longer competent to rule the kingdom. Lotharon talks in incoherent mumbles that only the Queen seems capable of deciphering. Queen Bella is Lotharon's second wife. She is shaped like a gumdrop, and although the kingdom loves her, Humperdinck despises her simply because all stepmothers are meant to be evil. Bella speaks for the King since no one else is capable of understanding his mumbles.