Muzan Kibutsuji is the main antagonist of Demon Slayer, a demon king who leads the Twelve Kizuki while hiding among humans. His soft, aristocratic voice contrasts sharply with his cruelty, which is why short clips of him speaking have become popular for edits and reaction videos. Fans collect his lines in parts and series, using them to signal a villain's arrival, a cold threat or a sudden shift in power. Because the character remains one of anime's most recognisable villains, his voice still works instantly, even for viewers who only know Demon Slayer from clips and memes.