Kazuma Satō is a Japanese teenage shut-in NEET who died attempting to save someone from a slow-moving tractor he mistook for speeding. After death, he met the goddess Aqua and chose to bring her along when transported to a fantasy world to defeat the Demon King. There, he became an adventurer leading a party with Aqua, Megumin, and Darkness. He and his party were later transported to the Isekai Quartet world after pressing a mysterious button. In this crossover, he attends school in Class 2 and serves on the Disciplinary Committee alongside Tanya von Degurechaff and Demiurge. He maintains an average build, slightly spiky chestnut-brown hair, and green eyes in both worlds. In the Isekai Quartet setting, he wears his standard adventurer attire: a gold-trimmed green mantle over a white shirt, pants, and leather boots. Kazuma exhibits a complex personality marked by laziness and a preference for relaxation, making him favor the school environment over his original world. He frequently expresses frustration and impatience, particularly due to his party's antics. He is notoriously perverted, using his Steal skill to take female characters' underwear, peeping on classmates during beach trips, and attempting to sneak into the nurse's office, actions that often draw discipline from Tanya and Demiurge. He is sarcastic, blunt, and champions "true gender equality" to justify retaliating against others regardless of gender. Despite these traits, he shows underlying kindness and reliability in critical moments, protecting Ainz Ooal Gown and his guardians from Aqua's purification and defending Albedo during confrontations. He forms a rivalry with Subaru Natsuki over their shared origins, though he envies what he perceives as Subaru's easier life. Kazuma also displays cunning and manipulative behavior, tricking classmates about monster dangers and deceiving Captain Weiss about Valentine's Day plans. Statistically, Kazuma possesses average physical and magical capabilities but exceptionally high luck and above-average intelligence. His combat style relies on cunning, strategy, and opportunistic use of basic skills. Key abilities include: - **Steal**: A thief-class skill taking a random item from a target, influenced by his luck stat. It frequently results in stealing female underwear. Effectiveness varies, failing against powerful beings like Reinhard van Astrea due to divine protections. - **Stealth**: Allows near-undetectability, though some characters can still sense him. - **Snipe**: An archer-class skill granting high projectile accuracy, dependent on luck. He applies this skill using a slingshot in the Isekai Quartet world. His high luck proves crucial in scenarios like disabling the Mobile Fortress Destroyer during Field Day. He also uses skills like Bind and basic elemental magic in his original world, though less prominently in Isekai Quartet. Kazuma maintains intricate relationships within the Isekai Quartet world: - **Konosuba Party (Aqua, Megumin, Darkness)**: He frequently expresses annoyance and embarrassment but demonstrates care, feeling joy at receiving their valentine chocolates. He protects them from threats, including preventing Aqua from purifying undead allies. - **Chris (Eris)**: Shares a friendly yet teasing dynamic, often referencing the underwear theft. Chris later warns him death in this world is permanent. - **Vanir**: Their relationship is contentious, with Vanir exposing Kazuma's inappropriate intentions during physicals. - **Re:Zero Characters**: He rivals Subaru Natsuki based on similar backgrounds. He expresses anger toward Ram after she reports his theft attempt to Roswaal and admits hostility toward Julius upon meeting. - **Tanya and Demiurge**: He fears both as Disciplinary Committee members. Tanya respects his usefulness despite intimidation, suggesting she would recruit him into her military. Demiurge disciplines him. - **Ainz Ooal Gown and Guardians**: He develops a protective stance, particularly during Aqua's confrontations. He questions Albedo about her succubus abilities but later finds her eccentric. - **Shield Hero Characters**: He assists Raphtalia in locating Naofumi Iwatani and explaining the crossover world. Naofumi develops a negative impression after Vanir exposes Kazuma's perverted actions. Across media, Kazuma evolves from a self-centered NEET to someone valuing his relationships. In his original series, he initially seeks to return to Japan but ultimately chooses to stay in the fantasy world after recognizing his attachment to his party. This development continues in the Isekai Quartet world, where he transitions from reluctance to active participation in school activities, though he remains the only character preferring the crossover world. His romantic subplot with Megumin progresses from mutual attraction to a committed relationship described as "more than friends, less than lovers."