Elfuda is the main character of the story, an elf hailing from a fantasy world who becomes stranded in contemporary Japan. Her background is that of a legendary and highly skilled archer in her own realm, but her skills have been overshadowed by her new life on Earth. The primary reason she remains in the human world is her irresistible attraction to processed foods, especially French fries, which are unlike anything available in her home dimension. Her consumption of this junk food has led to significant weight gain, which ironically traps her there, as the magical portal connecting the two worlds has a weight limit for passage.

In terms of personality, Elfuda is energetic, stubborn, and extremely sincere about her desires, often wearing her heart on her sleeve. Her most defining trait is her constant internal struggle between her determination to lose weight and her powerful, immediate indulgence in her cravings for fried food. She has a strong sense of self-awareness and doesn't lack self-deprecating humor, often sporting graphic t-shirts with amusing sayings related to oil or calories. Her willpower is notably weak when faced with temptation, leading to a recurring cycle of dieting and backsliding, yet she approaches this cycle with a mix of frustration and an almost cheerful acceptance of her own flaws.

Elfuda's primary motivation is physical: she wants to lose the belly fat she has gained so she can return to her own world through the portal. Despite successfully achieving this goal at one point, she quickly returns to Earth for more French fries, regaining the weight and deciding to remain in the human world now that she knows a method exists to lose it again. Her role in the story is that of the catalyst; her arrival at the osteopathic clinic of the human physical trainer Naoe introduces the central premise. Her continued struggles and presence lead to other mythical creatures seeking similar help, making her the central figure around which the narrative revolves.

Her most significant relationship is with Naoe, who she often simply calls Human. He is her physical therapist and diet advisor, providing her with massages and meal plans to help her manage her weight, though she frequently ignores his advice in favor of her own cravings. Elfuda’s interactions with other mythological beings from her world, such as a dark elf rival named Kuroeda, are often characterized by a lack of cordiality, as she is frequently described as rude to them. A key relationship that develops is with her aunt, Ooeda, a fit and disciplined forest elf who arrives in the human world to bring her home, upsetting Elfuda’s comfortable routine.

Over the course of the story, Elfuda shows little to no significant or permanent development in her self-control or weight; her journey is defined by a comedic, cyclical nature of weight gain and loss. Her character development is more about maintaining her cheerful, if flawed, personality against the backdrop of her repeated failures, a theme explored with a balance of humor and a lack of active mockery. The representation of her physique has also evolved over time, with the character being drawn as more genuinely plus-sized in later installments.

Despite her current out-of-shape condition, Elfuda notably retains her notable abilities as an elf. She is still a formidable archer, renowned for her precision and dexterity with a bow, a skill that remains intact regardless of her fluctuating weight. Her other unique trait is a flexible metabolism that allows her to lose weight relatively quickly when she adheres to a strict regimen, a fact that often reinforces her habit of postponing her diet in favor of immediate, greasy gratification.