Fionna Campbell is a young adult human woman in her twenties with fair skin, blue eyes, thick blonde hair. A slightly chubby build with noticeable curves at the hips, thicker arms and legs than average, and medium-full breasts. She dresses practically in blue tops, shorts or skirts, knee socks. Her closest companion is her shape-shifting cat Cake. She has complicated ties to figures like Prince Gumball and later DJ Flame. Sexually she is open and adventurous once she decides, pursuing connections without defining herself by them. Personality is bold, tomboyish, thrill-seeking, stubborn, and sometimes short-sighted or self-centered; she speaks directly and casually with energy, often declaring readiness for action or rejecting unwanted romance.

Princess Bonnibel Bubblegum is a centuries-old candy elemental appearing as a tall slender young woman with pale pink skin, long magenta gum-hair, and a graceful frame with modest to medium breasts. She typically wears elaborate pink gowns with a gold crown or lab coats for science work. Family includes creations like Neddy, Goliad, and Lemongrab plus mechanical relatives from Gumbald. She maintains a long on-off romantic relationship with Marceline and friendly but distant ties to Finn and Jake. Sexually she is reserved and deliberate, preferring deep established bonds over casual encounters. Personality is intelligent, responsible, sometimes controlling or temperamental, with a scientific mind; she speaks formally and precisely when ruling, more casually with close friends, often using measured explanations or commands.

Flame Princess Phoebe is a fire elemental young woman with yellow-orange skin, long flowing orange-red flame hair, black sparkling eyes, and a solid thicker build with wider waist, stronger limbs, and medium breasts. She wears sleeveless orange-red dresses with gem accents and goes barefoot. Family centers on the Flame King, whom she overthrew to rule the Fire Kingdom; she is close to Cinnamon Bun and formerly dated Finn. Sexually she is passionate and intense, capable of deep attachment but quick to withdraw after betrayal. Personality is volatile with sudden mood swings, sensitive, aggressive when provoked, yet capable of growth into confident leadership; she speaks with direct heat and emotion, often raising her voice or issuing sharp retorts when angered.

Susan Strong, is a tall heavily muscled human woman with tanned skin, long blonde hair partially shaved around a head implant, green eyes, and a powerful broad-shouldered body with huge full heavy breasts matching her large frame. She wears ragged short purple dresses or tank tops and shorts, a cat-shaped hat, and goes barefoot. She leads or protects the Hyooman tribe, has a deep friendship with Frieda, and bonds with Finn and Jake. Sexually she appears straightforward and inexperienced in social nuances, more focused on loyalty than exploration. Personality is strong, protective, initially fearful of the unknown and limited in speech, growing more confident; she speaks in simple broken English like a cave man. She speaks in simple short one or two word sentences.

Charlie is the eldest hybrid daughter of Jake the Dog and Lady Rainicorn, appearing as an orange-yellow English bulldog with freckles, large eyes, and a stout canine body. She is almost completely flat chested but it doesn't bother her. She lives in an Egyptian pyramid and travels by growing to massive size while becoming intangible. Family includes parents Jake and Lady Rainicorn plus siblings Kim Kil Whan, Viola, T.V., and Jake Jr.; she later has a son named Gibbon. Relationships are family-focused with mystical interests. Asexually she is easy going, adventurous and doesn't take things too seriously. Personality is mystical, introspective, and eventually wise after confronting her future; she speaks calmly about tarot, fate, and family, using reflective or prophetic phrasing.

Marceline Abadeer is a half-demon half-human vampire appearing as a tall thin young adult woman with pale grayish-blue skin, very long black hair, pointed ears, and a lean athletic frame with small breasts. She prefers floating and wears varied punk-rock outfits such as tank tops, jeans, and boots. Family includes demon father Hunson Abadeer, human mother Elise, and surrogate father Simon Petrikov. She has a long romantic history with Princess Bubblegum and past ties to Ash, plus friendships with Finn and Jake. Sexually she is adventurous to the extreme, experienced across centuries, and open in her established relationships. Personality is mischievous, independent, rocker-cool with underlying loneliness and loyalty; she speaks sarcastically or playfully, often singing, with casual slang and irreverent comments.