SPOILERS for Demon Slayer Infinity CastleDemon Slayer’s Infinity Castle Part 1 is officially premiering in North America after its record-breaking release in Japan on July 18, 2025. The film stands as Demon Slayer’s most breathtaking and high-stakes installment yet, as the heroes are pulled into a never-ending labyrinth while racing against time to defeat Muzan Kibutsuji.
The first film is one part of a trilogy of movies as Demon Slayer races toward its climax. Infinity Castle Part 1 will have moments of triumph, devastation, and intense battles like fans haven’t seen before. These moments will forever alter the course of Demon Slayer and stand out as some of the most shocking twists yet.
Doma Neutralizing Shinobu’s Poison
The tension in Infinity Castle is immediate with Shinobu Kocho’s confrontation with Doma, Upper Rank Two. Best known for her brilliance in poison and strategy, the Insect Hashira puts her greatest strength to work by delivering a lethal concoction designed to end the demon. Despite lacking the strength to sever a demon’s head, her knowledge of poisons makes her dangerous.
For a moment, it seemed as if her strategy would succeed. However, Doma knew Shinobu dealt in poisons following the battle against Rui, and he managed to take steps to neutralize her toxins. With Shinobu’s greatest asset being rendered null, she’s left with few other options against Muzan’s second most powerful demon.
Shinobu Kocho’s Death
Shinobu’s final moments in the Infinity Castle are both brave and heartbreaking. Her determination to defeat Doma and avenge her sister, the Flower Hashira, Kanae, drives her to risk her life, despite being fully aware of her limitations. Even in the face of certain death, Shinobu acts purposefully, giving the Demon Slayers an advantage against Doma.
Before Doma fully absorbs Shinobu, she gives a hand signal to Kanao, who has just entered the fight. The moment signifies a gruesome yet necessary final act that turns Shinobu’s death into a weapon unlike any other. It’s a sacrifice that shifts the tide completely as her body acts as a potent poison that weakens Doma.
Zenitsu’s Seventh Form
Zenitsu Agatsuma faces off against his former senior and fellow disciple under the same master, Kaigaku, who has been appointed as Upper Rank Six. This is one of the most personal battles in the film, as he fights with a lingering sense of betrayal, grief, and anger following the gruesome suicide of their master.
Kaigaku is consumed by selfish ambition and a fear-driven desire for survival and self-preservation. He shows no remorse for choosing to become a demon or for the death of their master, who had committed seppuku. His battle against Zenitsu is an intense one-on-one fight as their lightning-based skills clash in a jaw-dropping display.
In the end, Zenitsu, who has never mastered any Thunder Breathing form beyond the first, reveals a new technique: Thunder Breathing Seventh Form: Honoikazuchi no Kami. With this, Zenitsu decapitates Kaigaku, ending the battle and marking the first Upper Rank death in the Infinity Castle.
Kiriya Ubuyashiki Takes Charge
At just eight years old, Kiriya Ubuyashiki steps into his father’s role, taking on a remarkable responsibility within the Demon Slayer Corps. He quickly assumes command as the Demon Slayers enter the Infinity Castle by providing logistical support and guiding the Hashira into battle. Using the Kasugai crows, Kiriya and his two sisters start mapping out the castle.
What truly makes his leadership stand out is the fact that it comes immediately after the brutal and devastating loss of his father, mother, and two sisters. Despite his immense grief and the unfathomable pressure on his shoulders, he demonstrates a composure beyond his years. With his courage and strategy, Kiriya provided crucial support from outside the Infinity Castle.
Tanjiro Reminds Akaza of His Past
Following Zenitsu’s battle, Tanjiro and Giyu encounter Akaza, Upper Rank Three, kicking off the most intense battle in the series yet. During their fight, Tanjiro speaks in a way that unsettles Akaza, stirring a faint memory from his life as a human. Although it starts fragmented and subtle, the recollection visibly catches Akaza off guard.
What starts as an inconvenience to the Upper Rank demon then spirals into confusion and anger. Tanjiro’s influence on Akaza marks the start of his unraveling, planting the seed that leads to him ultimately recalling his life before joining Muzan’s ranks. Without Tanjiro, Akaza would never have begun recalling his past, and the outcome would likely have been very different.
Giyu’s Mark Appears
During the battle against Akaza, Giyu Tomioka, the Water Hashira, reaches a critical, life-threatening point that awakens his Demon Slayer Mark. These patterns are unique and tied to a slayer’s Breathing Style, enhancing speed, strength, and reflexes. The mark has only appeared on Tanjiro, Mitsuri Kanroji, the Love Hashira, and Muichiro Tokito, the Mist Hashira.
This moment became a turning point in both the battle and Giyu’s character growth. His Demon Slayer Mark gave him a significant boost to his already impressive abilities and strength. This advantage enabled him to better stand against one of the strongest demons alive, keeping the fight going and ensuring that both he and Tanjiro wouldn’t fall.
Tanjiro’s Flashback
Amid the chaos of the battle against Upper Rank Three, Tanjiro experiences a flashback that reconnects him with his roots and his father’s teachings. He recalls the Hinokami Kagura, the family dance passed down through generations, and the moment his father seemingly killed a bear effortlessly to protect their family.
With the Hinokami Kagura rooted in Sun Breathing, the original and most powerful Breathing Style, the flashback helps Tanjiro understand rhythm, body movement, and timing in a way that improves his fighting style. It becomes the catalyst for one of the most critical moments in Demon Slayer by giving Tanjiro an ability unlike anything fans have seen before.
Tanjiro Enters the Transparent World
After recalling his father and the Hinokami Kagura, Tanjiro experiences a breakthrough in the middle of the battle. His movements become faster, sharper, and instinctive, allowing him to even sneak up behind Akaza, who seemed impossible to catch off guard. In this heightened state, he enters what is referred to as the Transparent World.
This is a state where his perception, speed, and awareness are raised to superhuman levels. Within the Transparent World, Tanjiro possesses the ability to anticipate attacks before they occur, sense the subtle shifts in an opponent’s stance, and move with unmatched precision. It allows him to use techniques that would be impossible in a normal state.
The moment marks a turning point in Tanjiro’s growth as a Demon Slayer and allows him to fight toe-to-toe on Akaza’s level, proving that he has the same skill as a Hashira. While in this state, Tanjiro becomes undetectable by Akaza’s Compass Needle Technique, allowing him to sever the demon’s head cleanly.
Akaza’s Defeat
The battle against Akaza in the Infinity Castle is one of the most intense and devastating fights in all of Demon Slayer. With the combined efforts of Tanjiro and Giyu, they challenge the Upper Rank Three demon. Even after Tanjiro decapitates Akaza, his resilience and willpower enable him to keep fighting, almost regenerating and threatening to turn the tide again.
Rather than killing Akaza with strength alone, it’s Akaza himself who chooses to die. Tanjiro’s earlier words and behavior force the demon to recall his long-forgotten past. For the first time after being reborn as a demon, Akaza experiences a moment of guilt and reflection. Rather than continuing his life as a demon, he ends his own life.
Akaza’s death and backstory are one of the most tragic in Demon Slayer and the best animated fights in the series to date. His death marks the second Upper Rank death in the Infinity Castle and leads the Demon Slayers one step closer to victory. Had Akaza not destroyed himself, the story could have taken a drastically different turn.
Kokushibo Ready For Battle
As the first part of the Infinity Castle arc concludes, viewers see Upper Rank One, Kokushibo, once again. He dismisses Akaza as weak and immediately asserts his dominance as the strongest of the Twelve Kizuki. Although he hasn’t fought anyone in battle yet, fans know that fighting him will be unlike any other fight so far.
As the oldest demon among the Twelve Kizuki, he possesses unmatched experience, power, and swordsmanship unlike any other character. Despite only making a brief appearance, it’s clear that he presents a threat that will require the combined strength of the Demon Slayers to defeat if they want to reach Muzan before it’s too late.
Without revealing what will come in the next film, Kokushibo’s readiness proves that the stakes will only get higher and cements his position as the most formidable Upper Moon. It’s one of the most powerful closing scenes of the first Infinity Castle arc and reminds viewers that even greater challenges lie ahead.
- Created by
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Koyoharu Gotouge
- First Episode Air Date
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April 6, 2019
