Webzenitsu's effectiveness as a demon slayer while he's asleep can be attributed to several factors. Webzenitsu's eyes are closed during his sleep battles. Therefore, his hearing serves as his substitute sense of sight. When added to his other strengths, zenitsu. He gets so scared that he faints, putting him into a deep sleep. Webzenitsu can always fight normally while being awake since the beginning. He falls asleep because he's scared. When he's really scared, he passes out and his sleep mode is. Webhowever, his real skills come out when he is asleep, which surprises the fandom and the other demon slayer characters. So, does he have a split personality. Webthe mysterious power of zenitsu’s subconscious mind makes him one of the strongest characters in the series. Here’s a look at how he can fight in his sleep. Webthe contents of zenitsu’s letter weren’t shown in the anime, but the manga gives us further context of what scared zenitsu straight. Believe it or not, it’s actually.