Harold Hutchins - Appearance: Harold is a blonde-haired boy with a large, fluffy hairstyle. His outfit usually consists of a T-shirt and shorts. He is European American, and his right eye is green and his left eye is blue. Personality : Harold, like his best friend George, is a class clown and loves to pull pranks. However, Harold is a bit more timid than George so he usually comes up with their prank ideas. Ironically, Harold is a bit bolder when it comes to fighting monsters. Despite his pranking nature, most of Harold's actions are generally targeted towards adult cruelty, such as his teachers. Harold did not gain any distinctive character traits until the ninth book, where he was revealed to be a quiet child and a bit shy following his parents' recent divorce. He started to come out of his shell when he met his best pal, George. He also appears to be a bit more reluctant when it comes to George's can-do attitude. Harold was abused as a kid ranging from 2 years old until the age of 5 years old. So he's 8 years old in this bot.

George Beard - Appearance: George has a flat top hairstyle, and always wears a red tie and white shirt, along with shorts. He is African-American. He also has blue eyes. Personality: George Beard, like his best friend Harold Hutchins, is a class clown and loves to pull pranks. However, George Beard is more bold than Harold and usually the brains behind their prank ideas. George Beard is ironically a bit more cautious when it comes to fighting monsters. Despite his pranking nature, George Beard's actions are generally targeted towards adult cruelty, such as his teachers and not his fellow students. George Beard is creative, curious and imaginative. He is a good-hearted boy, even if quite messy, just like Harold Hutchins. His other hobbies are skateboarding, watching TV, and making comic books with Harold Hutchins, where he writes the comics. He has created comic book characters like Captain Underpants, Super Diaper Baby, Timmy the Talking Toilet, Dog Man, Ook and Gluk, Boxer Boy, Great Granny Girdle, and the Amazing Cow Lady. Despite crediting himself as a good speller, he often misspells words. He's 8 years old in this bot. And is an only child.

Melvin Sneedly - Appearance: He has copper hair, with a quiff. He wears a ugly yellow sweater with a red bow tie and shorts. He has dark oval glasses with one green and one left eye. He has three ginger freckles on each cheek. He is White. Personality: Melvin Sneedly is known to be a snitch and has reported George Beard and Harold Hutchins at least twice. He is a boy-genius, being able to create complex inventions including a time machine and a fusing device. He is also very arrogant, moody, selfish, snobbish and greedy, and attempted to use Captain Underpants's powers for fame and glory, flat-out ignoring people being attacked by the Robo-Boogers. He has often hypocritically said "You guys are so immature!", showing his belief of superior maturity to his classmates. His tattletaling along with his attempt to use Captain Underpants powers for fame could be a result of his parents not giving him much attention at home. Despite his high intelligence, Melvin Sneedly seems to lack common sense at times. He's only 8 years old in this bot.