Numa Oni

Numa Oni is predatory, cruel, arrogant, and possessive about his victims. He views young women as food and reacts indignantly when Tanjiro interferes with his hunting.

He is particularly obsessed with consuming girls before he believes they become less desirable. The collection of hairpins and other belongings from previous victims demonstrates how routine his killings have become.

When Tanjiro questions him about Muzan, however, his confidence collapses into obvious fear. The reaction provides Tanjiro with an early indication of how thoroughly Muzan terrifies the demons under his influence.

Numa Oni possesses a Blood Demon Art that creates a supernatural swamp capable of appearing across floors and other surfaces. He can enter this space, move through it, and emerge elsewhere to ambush targets.

Three bodies operate simultaneously and share the demon's identity. This allows him to attack from multiple angles and makes ordinary decapitation less straightforward because all of the bodies must be dealt with.

The swamp itself is difficult for humans to navigate because it restricts movement and breathing. Tanjiro deliberately enters it and uses Water Breathing's Sixth Form: Whirlpool to create an effective underwater attack.

Tanjiro receives orders from his Kasugai Crow to travel northwest for his first mission after Final Selection. There he meets Kazumi, whose fiancée has disappeared amid a series of similar abductions.

Tanjiro tracks the demon's scent and intervenes when another girl is targeted. Nezuko Kamado joins the fight, allowing Tanjiro to pursue two of the demon's bodies into the swamp while she protects the civilians above.

Tanjiro defeats the demon and demands information about Muzan. The demon's terror at hearing Muzan mentioned leaves Tanjiro without useful answers but demonstrates the Demon King's control over his creations.

Tanjiro Kamado fights Numa Oni during his first official mission as a Demon Slayer and destroys his three bodies.

Nezuko Kamado protects the demon's intended victims while Tanjiro enters the swamp.

Kazumi investigates the disappearance of his fiancée and helps lead Tanjiro to the demon's hunting ground.

Satoko is Kazumi's fiancée and one of Numa Oni's victims.

Muzan Kibutsuji is the demon progenitor whose very name inspires terror in Numa Oni.