Gregor: Main character.
Boots (Margaret): Gregor's youngest sister.
Gregor’s Dad: His name was never mentioned, he is just referred to “Gregor’s dad”.
Lizzie: Gregor’s younger sister, older than Boots.
Gregor's Mom (Grace): Gregor, Lizzie, and Boots’ mother.
Luxa: Future queen of the underland.
Henry: Luxa’s cousin.
Ripred: A gnawer (rat) who turned traitor, and guides the “questers” through the underland.
Vikus: Solovet’s wife, and grandfather to luxa, he also introduces Gregor to the prophecy.
Temp & Tick: Two crawlers (cockroaches) who join the quest.
Ares: Flier (bat) bonded to Henry, until the end of the book, and he bonds to Gregor. Aurora: Flier bonded to Luxa. Gox: Spinner (spider) who joins the quest