According to the results of the anime’s second official character popularity poll — posted on the unofficial Weekly Shonen Jump News Twitter, Zenitsu ranked first among the show’s entire cast. Zenitsu is one of the series’ supporting characters. A fellow teenage member of the Demon Slayer Corps, he becomes a friend and companion to Tanjiro throughout his journey.
Like all Demon Slayers, Zenitsu practices a special breathing technique in order to enhance his combat prowess and imbue his attacks with elemental power. According to the Kimtsu no Yaiba Wiki, Zenitsu is a practitioner of the Thunder Breathing Style, which enhances his speed well beyond what the human eye can follow. Oddly, Zenitsu has only mastered a single of the style’s forms, though he has honed it to great effect. Unfortunately, his combat abilities only shine through once he has fallen unconscious, as his cowardly nature prevents him from fighting while awake. When the going gets tough, however, Zenitsu proves himself one of the most valuable fighters in the Demon Slayer Corps.
During this time, Zenitsu has seen character development of his own, growing from a cowardly figure to one of the series’ strongest and most reliable combatants. According to one fan on Reddit, this character development is one of the major reasons that Zenitsu stands out. Everyone enjoys an underdog story, and as an apparent weakling, seeing Zenitsu’s inner strength come out makes him one of the most appealing characters in “Demon Slayer.”