Demon Slayer: Infinity Castle Arc

Episode 12 — The Upper Moons Gather

08:5223:47

Ep 12 / 26

1080p

Demon Slayer Infinity Castle Arc official poster showing Tanjiro with flame breathing technique against dark castle background

AiringSeason 4

Demon Slayer: Kimetsu no Yaiba — Infinity Castle Arc

Kimetsu no Yaiba: Mugen-jou-hen

9.2(219K)

847K watching

Spring 2026

ufotable

26 eps · 24 min

ActionDark FantasySupernaturalDramaHistorical

Continue Ep 12

Synopsis

After the devastating battle against the Upper Moon demons, Tanjiro and his comrades are drawn into the Infinity Castle — a labyrinthine fortress that defies all natural laws. Inside, the Hashira face the most powerful demons they have ever encountered, while Tanjiro pushes his Breathing Techniques to their absolute limit. The final confrontation with Muzan Kibutsuji draws near, and not everyone will survive.

Studio

ufotable

Source

Manga

Episodes

26 / 26

Duration

24 min/ep

Premiered

Spring 2026

Broadcast

Sundays 23:15

Episodes

Demon slayer training scene with breathing technique visualization in a mountain dojo

EP 1

The Struggle of Breathing

23m

Multiple hashira demon slayers training together in an outdoor forest setting

EP 2

Hashira Training Begins

24m

Stone pillar hashira with muscular build demonstrating rock-breaking training techniques

EP 3

Stone Hashira's Trial

Flames of Fury

The Serpent's Path

Sound and Thunder

The Wind Pillar's Gale

24m

Mist hashira moving invisibly through fog in a moonlit bamboo forest

EP 8

Mist Through the Darkness

Water's Edge

The Castle Beckons

Infinite Labyrinth

The Upper Moons Gather

Upper Moon Three

TBA

Discussion

(4,291 comments)

SakuraBlade992h ago

The animation in this episode is absolutely insane. ufotable really went all out for the Upper Moon reveal. The way they animated Doma's ice techniques was breathtaking.

OtakuKing_JP1h ago

Agreed! The particle effects during the ice bloom scene had me rewinding it 5 times. Peak anime.

Young woman with bright eyes and casual style as anime community member

AnimeFanatic_Rei45m ago

ufotable has been cooking since the Mugen Train arc. Every season they somehow top themselves.

Young man with glasses and enthusiastic expression as anime fan

DemonSlayerFan_Hiro3h ago

SPOILER WARNING FOR MANGA READERS: The way they adapted chapter 187 was perfect. The pacing felt exactly right and they added some anime-original scenes that actually enhanced the story.

Person with dark aesthetic style and anime-inspired look

KuroNeko_Subs4h ago

The English dub cast is doing an incredible job this season. Zach Aguilar as Tanjiro has really grown into the role.

Person with strong opinion expression as anime sub vs dub debate participant

SubsOverDubs3h ago

Respectfully disagree, the original Japanese cast is irreplaceable. Natsuki Hanae IS Tanjiro.

Creative person with artistic expression as animation analysis creator

AnimationNerd_Yuki6h ago

Frame-by-frame analysis: the sakitsu breathing animation uses over 340 unique frames in the 8-second sequence. For context, most anime use 8-12 fps. ufotable was running at 24fps for that entire scene.