Kobeni Higashiyama comes from a large family of at least eight sisters and two brothers, including a younger high school-aged brother named Nobana. Severe financial hardship led her parents to compel her into work to fund Nobana's college education. Choosing between limited options, she became a Public Safety Devil Hunter instead of a sex worker, sacrificing her own desire for college. Her family dynamics were abusive and toxic, and she later felt relief severing ties with them. Physically, she is a young woman with short brown hair, usually tied in a ponytail and featuring bangs framing the right side of her face. She has brown eyes with white pupils and four moles: two under her left eye, one near the lower right side of her mouth, and one on her left cheek. Her standard outfit is a professional suit, often accessorized with two red hair clips on her head's left side. For special events, like a newbie welcome party, she wore a hand-me-down dress from an older sister that others deemed cute. Personality-wise, Kobeni exhibits extreme timidity, anxiety, and pervasive cowardice, especially in life-threatening devil encounters. She suffers frequent panic attacks, paralyzing terror, and emotional breakdowns, as demonstrated by her hysteria over potential starvation while trapped by the Eternity Devil. This fear often results in clumsiness and poor judgment under pressure, driving drastic actions like threatening Denji at knifepoint to sacrifice him or falsely accusing colleagues of espionage. However, she shows moments of remorse and deep gratitude, particularly toward Hirokazu Arai after he shielded her from an attack at the cost of his life. Contradictorily, Kobeni displays remarkable cool-headedness and efficiency against human adversaries or in combat. She possesses exceptional physical prowess, including enhanced strength capable of cleanly severing a man's arm with a knife and enhanced agility enabling her to dodge devil attacks and traverse unstable surfaces. Her combat skills feature proficient knifemanship and marksmanship, evidenced by her solo defeat of the Katana Man in human form and forcing Akane Sawatari to retreat. She also excels in non-combat areas like driving and dancing, achieving perfect scores in rhythm games like Dance Dance Mushroom. She maintains a secret contract with an unnamed devil whose abilities remain undisclosed. Her story begins assisting survivor evacuations during the Bat Devil arc. Significant involvement follows in the Eternity Devil arc, where escalating fear drives her to attempt betraying Denji. After Hirokazu Arai dies shielding her in the Katana Man arc, she single-handedly rescues Denji from Akane and the Katana Man, revealing her latent combat abilities before breaking down and vowing to quit. She delays her resignation to receive an upcoming bonus. Later paired with the Violence Fiend, she patrols and undertakes missions like confronting the "Grape Devil." In the International Assassins arc, she participates in protecting Denji, enduring traumatic events including her car's destruction and transportation to Hell, where she witnesses the Darkness Devil's slaughter. The Violence Fiend sacrifices himself to save her, prompting her permanent resignation from Public Safety. Post-resignation, Kobeni works at Family Burger, a fast-food restaurant, enduring physical abuse from her manager. During a confrontation, her pleas for help inadvertently summon Pochita (in Chainsaw Man form), who demands a hamburger. Her attempts to serve him result in repeated accidents, spilling food and escalating chaos. Pochita kidnaps her, takes her for ice cream she finds tasteless, and forces her to play a dance game, which she completes perfectly. Makima attacks during this encounter; Pochita shields Kobeni, injuring himself. Kobeni survives but remains detached from devil hunting thereafter. Throughout her journey, Kobeni's primary motivations are survival and financial necessity, not heroism. Her character arc emphasizes an ordinary individual navigating extraordinary horrors, with her resilience and unexpected competence enabling her to outlive many peers despite pervasive fear.