Demon Slayer: Kimetsu no Yaiba Episode 3: Sabito and Makomo

Tanjiro keeps a journal detailing his training for his sleeping sister Nezuko. Sakonji Urokodaki, his trainer, begins Tanjiro's rigorous preparation for the Final Selection to join the Demon Slayer Corps, an ancient organization hunting demons.

Training starts with Tanjiro navigating a mountain full of booby traps, performing endless dry sword swings, enduring waterfall immersion to build stamina, and practicing breathing techniques.

A year passes in montage, with Nezuko still asleep after six months. Sakonji declares he has nothing more to teach and tasks Tanjiro with splitting a massive boulder as the final test before he can proceed.

Tanjiro hones his skills, dodging increasingly deadly traps—including those with knives and spikes—using enhanced strength and scent detection. Given a sword to mimic combat, his movements falter at first, leading to more failures, followed by days of repetitive blade swings under escalating difficulty.

Exhausted and failing to dent the boulder after countless attempts, Tanjiro despairs. A masked swordsman wearing a boar's head mask—Sabito—appears, mocks Tanjiro's lack of progress and manhood, and challenges him to fight.

Sabito effortlessly dodges Tanjiro's attacks, counters by striking his chin and knocking him out, criticizing that Tanjiro has only memorized techniques without internalizing them physically. He urges Tanjiro to keep pushing forward.

Tanjiro wakes to a young girl named Makomo, who explains he must train to death to surpass his limits and internalize his training. She bandages his wounds and offers guidance.

Sabito returns for repeated spars, dominating Tanjiro until the boy finally adapts, defeats him in a showdown, and channels his full power to slice the boulder clean in half.

As Tanjiro celebrates, Sakonji arrives, removes his mask to reveal a smiling fox face, and mutters that he's leaving the rest to "them." Sabito and Makomo vanish into the forest, their presence left ambiguous.