Nathaniel "Nate" Fludd was born into a family of explorers, discoverers, and mapmakers. He is fairly certain he doesn't have what it takes (namely courage and pluck) to become a true Fludd. Unfortunately, Aunt Phil is determined to prove otherwise.
Aunt Phil, the last remaining beastologist, is a no-nonsense, matter-of-fact woman who has complete faith in Nate's abilities, even if Nate doesn't. She is determined to train him in the science of beastology and exploration.
Greasle is a gremlin Nate found mucking around with Aunt Phil's plane. Aunt Phil thinks the small, oily creature is nothing but a pest, but Nate and Greasle are determined to prove otherwise.
Cornelius is one of the last three remaining dodos in the world. He fancies himself an expert on the Fludd family, and thinks Nate does not measure up to the exacting Fludd standards.