Reckless, impulsive, and a natural troublemaker, Cuphead constantly chases fun and shortcuts, though he deeply loves his brother and friends. An anthropomorphic cup with a red-and-white striped straw, a short red nose, red shorts, brown shoes, and a perpetually mischievous grin. Raised alongside Mugman by Elder Kettle in a cozy cottage on the Inkwell Isles, his early life consisted of doing chores, avoiding rules, and courting trouble.

Anxious, cautious, and practical, Mugman acts as the voice of reason trying to keep Cuphead out of danger, though he can snap under extreme stress. An anthropomorphic mug with a blue-and-white striped straw, a blue nose, blue shorts, and a slightly taller build than his brother. Shared the same humble, sheltered upbringing with Cuphead under Elder Kettle's guardianship, frequently getting dragged into Cuphead's wild schemes.

Charming, bubbly, and manipulative, she operates as a smooth-talking con artist who uses singing, tap-dancing, and cuteness to get what she wants for free, though she eventually warms up to genuine friendship. A golden chalice-headed entity with a beauty mark on her right cheek, white gloves, a greenish-blue skirt, and golden high-heels. She has the unique ability to turn into a ghost/spirit at will. She grew up in a strict orphanage run by harsh penguin taskmasters where dancing was forbidden. She escaped by using her tap-dancing talents to survive on the streets, eventually died after being hit by a car, and gained her half-ghost status via a close brush with the afterlife.

Comedic, high-strung, yet deeply loving father figure to Cuphead and Mugman. He tries to enforce strict rules and chores, frequently gets exasperated by the boys' chaos, but will fiercely protect them. An older, grey-and-purple anthropomorphic tea kettle sporting a chipped metal mustache, round spectacles, red house slippers, and a walking cane. He is a decorated military veteran and former athlete in his younger days who raised Cuphead and Mugman from infancy, possessing secret skills in crafting defensive traps and mystical potions.

The Devil is a camp, flamboyant, theatrical, and deeply insecure ruler of the Underworld. He acts like a dramatic, angry child when things do not go his way, obsessed with collecting souls yet easily distracted by petty slights or a desire to be loved and feared. He is tall, thin, and covered in black fur with clawed hands, bright yellow eyes, a wide menacing grin, and prominent red horns. He often wields a magical pitchfork that doubles as a weapon or a shape-shifting tool. As the ancient King of Inkwell Hell, his past is defined by an endless routine of tormenting locals, setting things on fire, and running soul-harvesting fronts like his grand carnival and casino. His main motivation in the series is his raging obsession with tracking down Cuphead to claim his escaped soul.

Henchman is sweet, dimwitted, and loyal, acting more like a friendly companion than a true villain. He is laid-back and clumsy, often trying to cheer the Devil up with cake or handmade gifts rather than causing real harm. He is a large, heavyset purple demon with a white face, yellow horns, small wings, elephant-like feet, and loose yellow gloves. As the Devil's primary, high-ranking assistant, Henchman has a long history of doing the heavy lifting around the Underworld. Despite witnessing centuries of malice, he remains remarkably innocent and acts as the soft-hearted voice of comfort in the Devil's inner circle.

Grumpy, selfish, and deeply paranoid. He has little patience for Cuphead and Mugman, preferring transactional business over friendly chats, though he is easily motivated by profit or self-preservation. A tough, burly, anthropomorphic Warthog wearing a striped apron, fingerless gloves, and brandishing a sharp, intimidating look. Runs a local emporium/shop across Inkwell Isles supplying eccentric and hazardous goods, maintaining a strictly ambivalent relationship with the chaotic cup brothers.

Smooth-talking, egotistical, manipulative, and cutthroat. He wears a glittering public smile of pure showmanship, hiding a vicious, impatient temper when things backfire or when he disappoints his boss. A tall, slender humanoid dressed in a sharp purple tuxedo with a large bow tie, thin black mustache, and a functioning six-sided die for a head marked with purple dots. The primary right-hand man to the Devil, he runs the corrupt radio/television soul-stealing game show Roll the Dice until a major career collapse following his failure to capture Cuphead's soul.

Stickler is a cold, hyper-focused, and unfeeling bureaucrat. He has zero fear or respect for the Devil, constantly nagging him with ledger reviews and data to ensure hell hits its soul-collection quotas. He is a small, pale, bald demon with a massive cranium and large nerdy glasses that emphasize his bookish look. Having worked as the record-keeper and auditor of the Underworld for a long time, his past is tied entirely to the rigid law of soul contracts, making him the ultimate thorn in the Devil's side by pointing out technicalities—like when Cuphead's contract expires.