Thunder Breathing

Thunder Breathing recreates the movement of lightning, the kind of swift strike that seems to tear across the heavens, and pours it into the user's steps and cuts. Its forms favor blinding velocity and instant attacks meant to crush a foe in a single moment, with the wielder picturing electricity crackling around them. Zenitsu Agatsuma observed that the style funnels power into the legs and wrings the most out of every muscle and vessel there. The art closely resembles the real quick-draw sword method known as iaijutsu.

It branched from Sun Breathing through one of Yoriichi Tsugikuni's students, who, unable to match Yoriichi's innate gift, was instead taught a tailored method built around his own strengths and weaknesses that eventually grew into Thunder Breathing. Among the Demon Slayer Corps, the former Rumble Hashira, Jigoro Kuwajima, is a known cultivator of the style.

The style holds six standard forms, with the first treated as the bedrock for all the rest. Zenitsu later devised a Seventh Form so he could match Kaigaku, his former senior disciple under Jigoro who had risen to Upper Rank Six. The First Form, Thunderclap and Flash (Episode 12), draws the blade, dashes ahead at terrific speed, and lands a horizontal cut before the eye can follow, then resheaths. Zenitsu extended it into Sixfold and Eightfold, repeating the strike six or eight times in a blur, and into Godlike Speed, which pushes the velocity even higher at the cost of his legs. The remaining standard forms, such as Distant Thunder and Rumble and Flash, were displayed by Kaigaku using actual lightning. Zenitsu's own Seventh Form, God of Fire Thunder, sweeps a single low slash trailed by a lightning-like dragon.

Jigoro Kuwajima trained the style as a cultivator and former Rumble Hashira, the title given to a Thunder Breathing user who reaches the Hashira rank. His two pupils took very different paths: Zenitsu Agatsuma could only ever learn and perfect the First Form, while Kaigaku grasped every form except that one before defecting to become a demon. Only two styles have ever been fused with a demon's Blood Demon Art; Moon Breathing is the other, but Thunder Breathing is the sole one shown both in its pure form and in its demonic variant, since Kaigaku's lightning appears black with a blue outline.