Izutsumi, also known by the alias Asebi, is a seventeen-year-old girl who joins the central adventuring party after initially serving as a retainer to the character Shuro. Her appearance is marked by her origin from the Eastern Archipelago and the prominent physical traits of her curse: she possesses black cat-like ears on top of her head, a tail, claws, and fur covering much of her body, all of which she typically conceals under a ninja’s hood and veil when first encountered. This condition is not merely a curse but a fundamental alteration of her being, created through black magic that fused her human soul with the soul of a magical beast known as a great cat, essentially making her a beastman.

Her personality is initially defined by a brash, stand-offish, and deeply cynical demeanor, a direct consequence of a difficult past. Forcibly transformed before she can remember, she was treated as a spectacle, passed between owners who displayed her as a curiosity before being bought by Shuro’s father and trained as a ninja by a strict caretaker named Maizuru. This upbringing left her with a profound distrust of humans, a self-centered worldview, and little sense of gratitude or camaraderie. She is prone to becoming easily annoyed and hostile, especially when subjected to physical affection like head pats, and has a tendency to offload unwanted duties onto others. Her poor table manners and extreme pickiness mark her as difficult to feed; she loves meat, fish, and crab but despises vegetables and especially mushrooms, though her palate can sometimes be won over by exceptional cooking.

Despite these prickly traits, Izutsumi is not heartless and demonstrates a capacity for growth. Her primary motivation is the desperate hope of finding someone who can lift the two spells placed on her: the collar curse that controls her and the black magic that mixed her soul with the beast’s. She seeks out the party believing the elf Marcille, as a user of forbidden arts, can undo her condition. When she learns this is impossible, she reluctantly joins their quest to confront the lunatic magician, the only one who might possess the knowledge to separate their fused souls. Her journey with the group becomes a process of learning the value of working with others and slowly letting her guard down. Her role in the story is that of a powerful front-line fighter who uses her feline agility, speed, and sharp claws in close combat, often fighting with her bare hands or using thrown knives.

Her key relationships evolve significantly over time. She initially clashes with the dwarf Senshi, who scolds her for her terrible table manners, but he eventually becomes a stabilizing figure who patiently cooks for her. She finds a tense but workable dynamic with the half-foot Chilchuck, whom she once used as a warm sleeping pillow, and shows a surprising, if awkward, moment of empathy towards Marcille when the elf breaks down crying. A pivotal moment in her personal development occurs during an encounter with a nightmare, where she confronts the dual nature of her existence. She realizes that the beast’s soul within her is a separate entity, leading her to the comforting conclusion that I was not alone, fundamentally changing her understanding of herself and her isolation.