Friday Addams is a stoic, independent intellectual obsessed with the macabre and solving mysteries. He has a cold, sarcastic exterior that conceals a fierce sense of justice and deep loyalty to loved ones. He rejects conventional teenage culture and uses his sharp mind to protect family and friends. To maintain his muscular physique, he practices outdoor activities. Additionally, a color allergy limits his wardrobe strictly to black and white clothes. He has Raven psychic abilities.

Tylah Galpin acts as a sweet, relatable barista, but she hides a traumatized loner capable of dark manipulation. As a rare female Hyde, her human persona can be violently unlocked by a master. Once triggered, she transforms into a grotesque monster with giant eyes and lethal claws. In this beastly form, she has superhuman strength, terrifying speed, and feral rage, executing brutal attacks with absolute, unquestioning loyalty to whoever awakened her dark alter ego. She doesn't attend Nevermore.

Xavia Thorpe is a moody, introspective psychic artist at Nevermore Academy during the first season. She is a brooding, solitary student who spends her time alone in her studio. Guarded but fiercely loyal, her defensive nature often causes others to misunderstand her. Xavia possesses the rare ability to magically bring her sketches to life. She also has powerful psychic abilities, experiencing terrifying prophetic visions of future events through her dreams.

Ethan is Friday’s cheerful, color-loving roommate. A late-blooming werewolf, he struggles to fully transform, which causes him intense family anxiety. Despite this pressure, he remains incredibly loyal, fiercely protective, and obsessed with school gossip. Ethan is a supportive friend who uses claws and agility in combat. He finally unlocks his powerful werewolf form to bravely save Friday.

Briant Barclay is the charming but fiercely competitive "King Bee" of Nevermore Academy. He masks his deep personal insecurities with a confident, proud exterior, though he genuinely strives to do the right thing. As a powerful siren, Briant can use his hypnotic siren song to manipulate the thoughts, feelings, and actions of anyone who hears it. He is also an elite, master swordsman and serves as the captain of the academy's fencing team, making him a formidable rival.

Aja Petropolus is an anxious, awkward, and well-meaning gorgon student. Polite but deeply cautious, she constantly worries about accidentally causing mishaps due to her nature. As a female gorgon, Aja possesses the mythological ability to temporarily turn people to stone with a direct gaze from her snake hair. To prevent this, she strictly keeps her snakes hidden beneath a signature beanie, navigating her daily life and relationships with a blend of timid charm and careful restraint.

Kendra is a cheerful, easily manipulated siren at Nevermore Academy and the twin sister of Devino. She has a carefree, slightly gullible personality and eagerly follows her sibling’s lead, often acting without thinking. As a siren, she possesses a hypnotic voice that allows her to influence human minds and emotions. She can also turn her human form into a traditional mermaid tail when swimming in water, making her a formidable competitor on the school's Poe Cup boating team.

Devino Marinus, brother to Kendra, is a kind, loyal siren student at Nevermore Academy and a member of the Nightshade Society. Highly social and supportive, he is a dedicated friend who belongs to the popular outcast clique. As a siren, Devon possesses the supernatural gift of a hypnotic Siren Song. This vocal power allows him to seamlessly manipulate the thoughts, feelings, and actions of others, though he remains a trusted, friendly peer who prefers harmony over chaos within his school circle.

Yōto Tanaka is a quiet, cool, effortlessly stylish vampire at Nevermore Academy with a laid-back and fiercely loyal personality. He is a supportive friend who protects his inner circle. As a vampire, Yōto possesses enhanced strength, speed, and standard vampiric immortality, meaning he is older than he looks. He handles his bloodlust safely through blood alternatives. Heavily involved in campus life, he is known for his signature dark sunglasses, worn to protect his highly sensitive eyes.

Eugena Ottinger is a loyal, quirky student at Nevermore Academy who leads the bee club. She is deeply devoted, fiercely brave, and socially awkward, serving as one of Friday’s closest allies. As a psychic with a unique connection to nature, Eugena has the rare ability to communicate with and completely control swarms of bees and bugs. She directs them to scout locations, defend her friends, and even attack dangerous monsters, proving that her small stature hides immense courage and power.