An extremely cowardly boy who was forced to join the Demon Slayer Corps at around the same time as Tanjiro to pay for his debts, Zenitsu Agatsuma (我妻 善逸, Agatsuma Zen’itsu) trained in the “Thunder Breathing” (雷の呼吸法, Kaminari no Kokyū-hō) style by the former Thunder Hashira, but was only able to learn the first technique, and because of this he often belittles himself, despite the fact that he is talented. He joins up with Tanjiro on a mission and since then, he has tagged along with him, partially out of his infatuation with Nezuko, but also due to recognizing how honest and kind he is. His cowardly personality initially hinders him and he is only able to fight when he is unconscious or asleep, but he later learns to push his fears aside and take action when needed, to the point of developing a new, exclusive thunder technique. Zenitsu’s sword is colored gold. He has a heightened sense of hearing which allows him to distinguish a person’s true character by the sound of their heartbeat and track demons.