Rex

Rex (full name Rex Grizz Quaternion) is a character in LetterStart.

Name

 * His first name means "king", and is also a cat, rabbit, or guinea pig of a breed with very fine short fur. It's also based on Tyrannosaurus rex, one of the most famous dinosaurs.
 * His middle name is derived from "grizzly bear".
 * His last name means a number that is in the form of "a+bi+cj+dk", where a, b, c, and d are rational numbers and i, j, and k are imaginary constants.