Reynold and Wren
Twins and main characters. The player chooses which of the two they want to play (the only real difference being the gender), and the other is kidnapped by the monsters, leading to the game events. Voiced by Sloane Letourneau (Reynold) and Gabriella Graves (Wren) in the animated series.
- Badass Adorable
- Half-Identical Twins
- Perky Goth: The siblings obsession with Halloween and Wren's clothing choice seem to imply this.
- Sibling Rivalry
- Sibling Seniority Squabble: Wren is exactly 10 minutes older than Reynold.
- Static Role, Exchangeable Character: You choose one to play as, the other is the Damsel in Distress/Distressed Dude. Or just a party member in Grubbins On Ice and 2.
- Took a Level in Badass: The sibling who got rescued in the main game is promoted to third party member in Grubbins On Ice.
Everett
The first friend the player sibling makes in the adventure. Voiced by Issac Ryan Brown in the animated series.
- Badass Adorable
- Black and Nerdy
- Official Couple: With Lucy, come 2. You even meet their daughter Halley.
Lucy
The second friend the player sibling makes in the adventure. Voiced by Allie Urrutia in the animated series.
- Ambiguously Brown: Err... rather "Ambiguously Asian." Her hairstyle heavily resembles Odango Hair and her personality reeks of Asian and Nerdy. It's never made clear or elaborated on anywhere else however.
- Badass Adorable
- Damsel in Distress: In Grubbins On Ice.
- For Science!
- Glomp: Does this to Everett at the end of Grubbins On Ice.
- Official Couple: With Everett, by 2. You even meet their future daughter, Halley.
- Wrong Genre Savvy
Dorian
A strange man who helps the heroes. Dorsilla's brother.
- Sibling Rivalry: And he's losing.
- Stealth Mentor
Dorsilla
A wicked witch who leads the candy theft.
- Badass Fingersnap: She snaps her fingers to summon the tornado that removes the player character's costume and deposits them away from her.
- The Dragon: Actually The Starscream.
- Manipulative Bitch
- Woman Scorned: Turning on Dorsilla is generally a bad idea.
Big Bones
The leader of Repugia, the monsters' dimension. He wants to devour every candy in the universe.
- Adipose Rex: Ruler of Repugia and morbidly obese.
- Big Bad: The main antagonist of Costume Quest.
- Grim Reaper
- Kevlard: When hitting him with a weak attack, he laughs as it bounces off his large gut.
- Not Quite Dead
- Stuck in the Doorway: Can't get out of the portal he's summoned from, due to being so large.
Araxia
Big Bones' right hand Crestwailer, and main villain of Grubbins On Ice.
Orel White DDS
The main antagonist of Costume Quest 2. A dentist who wants to eradicate halloween and candy from the timeline to create a dental hygiene utopia.
- Braces of Orthodontic Overkill: As a child. Turns out, they're not that permanent, and he sheds them prematurely during his redemption scene.
- Depraved Dentist
- Evil Overlord: He's known as "Overlord White" in the future.
- Freudian Excuse: Why is he so hell-bent on the destruction of Halloween, and candy in general? His mother was an obsessive, extremist dental hygienist and forced, among other things, Braces of Orthodontic Overkill, no candy at all and repeatedly brushing his teeth over and over again. (Which, ironically, will actually damage your teeth.)
- Future Me Scares Me: Kid Orel is extremely conflicted when confronted by his future self. After beating his grown-up self down, he resolves to be a better person.
- Mad Doctor
- My Beloved Smother: Key reason for his descent into villainy AND dentistry.
- Non-Standard Character Design: Stands out among the rest of adults.
- Obviously Evil
- Psychopathic Manchild: Is seen gleefully skipping through his top-secret warehouse, which actually houses a recreated plywood suburb where he alone can trick-or-treat door to door and collect all the candy he wants. He even has a temper tantrum when the machinery glitches and accidentally insults him.
- Slasher Smile: Every time he smiles.