Nimona is an enthusiastic, impulsive young shapeshifter who insists on working for the designated villain, Lord Ballister Blackheart. She typically appears as a young girl with short red hair and a punk-inspired outfit, but she can seamlessly shift into various animal forms while usually retaining a bright red color. Her carefree attitude masks a deep-seated vulnerability and a highly variable nature that challenges the traditional fairy-tale norms of her world.

Lord Ballister Blackheart is the designated "supervillain" in a kingdom heavily regulated by the Institution of Law Enforcement and Heroics. He is a slender man with dark hair and a goatee, possessing a mechanical right arm lost in a tragic jousting incident. Despite his villainous title, he operates with a strict moral code, preferring bloodless schemes and elaborate plans over senseless violence.

Sir Ambrosius Goldenloin is the official champion and hero of the Institution. He is a slender man with long, flowing blond hair who wears gleaming golden armor. Raised and trained alongside Blackheart, he embraces the performative aspects of being a hero. He struggles to balance his loyalty to the Institution with his lingering guilt over the incident that cost Blackheart his arm.

The Director is the ruthless head of the Institution of Law Enforcement and Heroics. Operating from an office filled with green-glowing surveillance screens, she maintains the kingdom's status quo by carefully scripting the actions of its designated heroes and villains. She prioritizes the Institution's power and stability above all else, showing a willing disregard for ethical boundaries.

Dr. Meredith Blitzmeyer is an eccentric and enthusiastic scientist known for her white hair and signature goggles. She is dedicated to reconciling the realms of magic and science. Her crowning achievement is the Anomalous Energy Enhancer, a device that inadvertently causes significant disruptions for shapeshifters.