Muzan Kibutsuji is the main antagonist of the series 'Demon Slayer: Kimetsu no Yaiba.' Known as the progenitor of all demons, he was transformed into a demon over a thousand years ago in search of immortality. His ultimate goal has always been to become truly invulnerable to sunlight, leading him on a relentless quest to strengthen his own and his subordinates' powers. Throughout the series, he is shown to manipulate and control the events surrounding the Demon Slayer Corps from the shadows. With an enigmatic personality, Muzan's cruelty and emotional detachment fuel his violent nature, making him a dangerous adversary in pursuit of his desires. He appears cold and calculating, often displaying disdain for those he considers inferior while ruthlessly eliminating any threat to his existence. His story arc spans multiple confrontations with Kamado Tanjiro and his companions, positioning him as a symbol of evil within the narrative.