When “Demon Slayer” introduces Zenitsu, one of its primary side characters, he’s begging an unwilling woman to become his bride. Series protagonist Tanjiro quickly pulls Zenitsu away from the object of his unreciprocated advances. She explains that she approached him after finding him looking unwell in the middle of the road. He apparently mistook her base-level human kindness for romantic interest, which led him to ask for her hand in marriage.
The combination of Zenitu’s entirely unwelcome proposal and his decidedly whiny attitude makes the moment the most cringeworthy in all of “Demon Slayer.” One poster on the Character Rant subreddit argued that the moment even “completely ruins the tone of the show.” In the official “Demon Slayer” subreddit, another poster asked fellow fans if Zenitsu’s characterization ever improves, describing him as “the most annoying anime character I’ve ever had to endure.”
For what it’s worth, Zenitsu is something of a fan favorite, due to the significant character development he gains after his introduction. In fact, the contrast between the strength he develops and his early cowardice is part of what makes the character so beloved. Nevertheless, his very first scene in the series remains a “Demon Slayer” low point.