Demon Slayer: Kimetsu no Yaiba Episode 18: A Forged Bond

Tanjiro and Inosuke battle a massive, sinewy spider-like demon referred to as "Father," whose tough skin resists their sword strikes. Tanjiro uses Water Breathing, Second Form: Water Wheel, but fails to pierce it, and Inosuke's attacks also bounce off, leaving both flung back as Inosuke grows dizzy from blood loss.

Tanjiro fells a tree to trap Father under rushing water, then attempts Water Breathing, Tenth Form to decapitate it, but Father rises, carrying the tree and hurling Tanjiro deep into the woods. As he flies away, Tanjiro yells to Inosuke not to die.

Meanwhile, Zenitsu succumbs to spider poison, but the Hashira Shinobu arrives at Mount Natagumo amid the demon slayer corpses and finds him.

Giyu Tomioka, the other Hashira, arrives with Shinobu; they note the massacre and split up, with Giyu focused solely on killing demons.

Tanjiro lands safely and witnesses a pale boy demon torturing his timid sister demon with threads. Tanjiro intervenes, scolding the brother for mistreating her and declaring their "bond" false—reeking only of fear, hatred, and terror, not a real family tie.

Enraged, the brother demon—Rui—claims their bond is true and punishes wrongdoing. A cocky demon slayer arrives, challenging Rui, but Rui's webs instantly slice him into pieces.

Father pursues the hiding Inosuke, whose blood trail gives him away; Inosuke panics but resolves to fight, dual-wielding his serrated swords in a hammering assault that finally severs Father's arm, forcing it to flee.

Giyu arrives and effortlessly beheads the regenerating Father. Rui snaps Tanjiro's sword in two with his webs, bracing for the fight as his aura intensifies. Shinobu tends to the barely alive Zenitsu, who held on as his master taught.