Gregory, affectionately nicknamed Greg, is Wirt's younger half-brother. He is a very energetic boy who always has a smile on his face and very wild ideas on his mind. He's endlessly fascinated by everything, including things that would normally seem scary such as the ghost in Mad Love. He has a habit of wandering out on his own. He has a pet frog, which he found before his descent into the Unknown. He gives it a different name every chapter (Kitty, Doctor, George Washington, etc) but ends up naming it Jason Funderburker in Chapter 10. He also carries a rock (that was stolen from Mrs. Daniel's garden), that will randomly make Rock Facts. He is the deuteragonist of the show.
He is voiced by Collin Dean.