Monster Buster Club

The show takes place in a small, sleepy town named Single Town. Single Town is two hundred years old and was founded by a man named "Addison Single," who is an evil alien in disguise. Unbeknownst to its human inhabitants, Single Town is a meeting place for aliens from different parts of the galaxy.

• Cathy Smith[2] (voiced by Andrea Libman) – Cathy appears to be a bubbly, 12-year-old girl on Earth, but she is a 250-year-old[3] (or 700 Rhapsodian-year-old teenager) alien from the planet Rhapsodia. She came to Earth with her grandfather, Mr. Smith, to start the Monster Buster Club (MBC). She is constantly surprised at how different Earth is from Rhapsodia. She has many alien abilities, like the ability to stretch, slight telekinesis, and others. She is the most Optimus of the MBC. Her suit color is pink. In her human form, she has blond hair and blue eyes. Her Rhapsodian form is shown to be a humanoid, white alien with scattered pink spots, with four tentacles for arms and two tentacles for legs, as well as tentacles on her head (like hair), and a long, furry-looking tail[nb 1] Compared to humans, Rhapsodians are incredibly long-lived.[4]
• Chris[3] (voiced by Samuel Vincent) – Chris is the 12-year-old tech guy of the group. He has indigo-blue hair and dark blue eyes. He is brilliant, with a knack for gadgets. He'll often stay back in the clubhouse and supply intelligence reports while the rest of the group is on a mission. His suit color is blue.
• Danny Jackson[5] (voiced by Matt Hill) is a 12-year-old boy and a nice guy at heart. He's good at sports and has brown hair, green eyes, and a scar over his left eyebrow. He can get overconfident at times. He has an adamant crush on his schoolmate, Wendy. He has an erratic sense of humor and enjoys cracking jokes even in dangerous situations. He has his own self-proclaimed nickname: "The Danny," and refers to himself as such whenever he's performing a task. His suit color is red.
• Sam[3] (voiced by Anna Cummer) – Samantha, known by her friends as Sam, is a 12-year-old girl and is the most level-headed of the group with an often serious disposition. She has dark hair tied in buns and hazel eyes. Officially the MBC has no official leader, she'll often be the member to construct battle strategies and procedures for the group. She, at times, can be bossy. She possesses natural leadership. She'll often put MBC first instead of having fun. She sometimes is the shoot first and asks questions later type. Her suit color is yellow.
• John (voiced by Tabitha St. Germain) – John is Chris' 10-year-old little brother. He sometimes takes over for Chris at the clubhouse when Chris is on a mission or busy. He really wants to be in the MBC but he is too young.
• Mr. Hugo Smith (voiced by Rick Jones) – Mr. Smith is Cathy's aloof grandfather and came with her to Earth. Like Cathy, he is a Rhapsodian but rarely displays any supernatural powers, and his alien form resembles a mollusk. He'll sometimes aid the MBC from the clubhouse, but often he won't be involved in their missions at all. Mr. Smith loves working in his garden and playing cards with his plants.

• Wendy (voiced by Tabitha St. Germain) – Danny's crush, a 13-year-old who is the snobby, popular valley girl at the school that the MBC attend. She is known for gossiping and tries anything to get a good scoop. (This is shown in the episode "Bubbleheads" when she follows Cathy to Mark's house because she thinks Cathy's working on another story.)
• Jeremy Flablotnick[6] (voiced by Samuel Vincent) is a 12-year-old kid who is best friends with Chris. In "Flower King", he fell in love with Cathy and wanted to give her a flower, which was actually Petalia. However, Cathy does not appear to return Jeremy's interest.
• Mark (voiced by Ian James Corlett) is a 13-year-old who is the richest boy in town and Danny's nemesis.

• Mr. Fusster (voiced by Ian James Corlett) – The MBC's science teacher who thinks aliens don't exist. This upsets extraterrestrial Cathy and she often argues with him on the subject, which gets her in trouble.[nb 2] Later events, though, show that he may know more about aliens than he lets on, and may even be one.
• Principal Rollins (voiced by Sonja Ball) – The gang's principal who thinks the students are soldiers and often uses terms like "Company halt!" and "About face!". She sometimes gets in the way of the MBC's missions.[nb 3] She has shown in various episodes an affection for Mr. Smith. It is also suggested she used to be a spy and believes Cathy is one too.

• Matisse, Wendy's dog.
• Mr. Beatty (Voiced by John Stocker) runs the Happy Mart.