Let’s not sugarcoat it: ‘Demon Slayer: Infinity Castle – Part 1’ doesn’t just swing for the fences — it rips the whole field out of the ground and sets it ablaze. From poetic deaths and power-ups to heartbreaks that hit harder than a Hashira’s blade, this movie throws everything it has at the audience… and then throws a little more just for fun.
It’s the first film in a three-part finale, but if you thought that meant pacing would be slow or stakes would be light — surprise! You clearly forgot who you’re dealing with. Ufotable doesn’t do chill. They dropped us straight into Muzan’s ever-warping, ever-maddening dimension and dared us to breathe.
So let’s talk about it. What just happened? Who got absolutely wrecked? And why are we suddenly crying over Akaza of all people?
Welcome to the Infinity Castle: Screaming
There’s no easing into the madness here. The movie opens with Muzan, very much not dead after the attempted kamikaze assassination by Kagaya Ubuyashiki, pulling a full villain move by yanking the entire Demon Slayer Corps into his personal realm: the Infinity Castle.
And this place? It’s less a fortress and more an architectural acid trip. Picture an infinite tower of mirrors, stairs, rooms, and despair, constantly shifting at the whim of one biwa-playing demon — Nakime — who conducts the chaos like a gothic orchestra.
Split up and disoriented, the Hashira and their allies are forced into battles they aren’t prepared for. And Muzan? He’s tucked away like a cocooned coward, marinating in flesh while he tries to outlast Tamayo’s humanization drug. A tactical genius, if that genius is pure evil in a suit and Michael Jackson hair.
Shinobu Kocho: The most lethal death you’ll ever see
Exclusive images of Shinobu vs. Doma from Demon Slayer: Kimetsu no Yaiba Infinity Castle! 🦋
▼ International Release Dates:https://t.co/zyxnw1Ygji pic.twitter.com/xW855VjHfv
— AnimeTV チェーン (@animetv_jp) August 30, 2025
Let’s talk heartbreak. Shinobu Kocho — the Insect Hashira with the sunny smile and razor tongue — finally comes face-to-face with Doma, Upper Rank Two, cult leader, cannibal, and the guy who murdered her sister. If you thought Shinobu had a chance in this fight, well… you were half right. She never expected to walk out alive. That was the plan.
Knowing her blade couldn’t decapitate demons, Shinobu laced her entire body with wisteria poison — enough to kill a dozen demons — and let herself get absorbed. Her body became a living weapon, a suicide mission wrapped in grace and fury. She knew Doma wouldn’t resist the chance to consume her, and when he did, she set the clock ticking on his downfall.
Her death is brutal. No soft fade-outs or melodramatic last words. Just pain, silence… and then Kanao arrives too late to save her — but just in time to avenge her. As Doma smirks and taunts, he doesn’t realize he’s already dying from within. Shinobu may be gone, but her revenge is brewing in his veins.
Zenitsu Agatsuma: Thunder boy, God mode activated
I bet zenitsu heard kaigaku’s steps and locked in 💀 he’s so cool in this scene 😭 pic.twitter.com/LYbZeCj1nb
— Saara🇵🇸|| (@SaaraAdem) June 30, 2024
And then there’s Zenitsu. Oh, Zenitsu. The nervous wreck who used to faint his way through battles just became the MVP of the movie — and possibly the entire arc. His opponent? Kaigaku, his former training partner, turned Upper Rank Six. Their fight is personal, petty, and absolutely electrifying — literally. Kaigaku, all ego and betrayal, represents everything Zenitsu hates and fears: weakness disguised as strength.
But Zenitsu isn’t here to cry this time. He’s here to finish things. And finish them he does, with a self-invented Thunder Breathing Seventh Form called “God of Fire Thunder.” It’s fast. It’s furious. It’s fatal. Kaigaku’s head rolls, and Zenitsu collapses from exhaustion — only to be whisked away to safety by a disguised Yushiro.
In a brief moment of post-battle peace, he gets a vision of his late master, who finally says what Zenitsu always needed to hear: he was proud of him. Try not to cry. You’ll fail.
The main event: Tanjiro vs Akaza – The demon with a soul
I hope Demon Slayer gets all the love in the box office cause what in the emotional roller coaster was that!!
Giyu & Tanjiro vs Akaza is a site to see 🔥 Also the soundtrack on this movie goes unbelievably hard 🫨 pic.twitter.com/LEqokJWVOI
— xLadyHokagex (@ailish_mailloux) September 12, 2025
Now for the crown jewel of the carnage: Tanjiro and Giyu vs Akaza. It’s not just a fight. It’s a psychological chess match layered with grief, growth, and ghostly memories. Akaza, the demon who killed Rengoku, is back — and he’s never been more dangerous. But Tanjiro is different now. He’s not just swinging swords. He’s playing the long game.
By unlocking the Transparent World — a state of pure perception where emotion is erased — Tanjiro becomes unreadable to Akaza’s attack-sensing technique. That mental shift gives him the edge to land a clean beheading. But Akaza, ever the stubborn monster, doesn’t die. Instead, his body regrows from nothing but rage and regret.
Then the twist hits. We see who Akaza was before Muzan: a boy named Hakuji, stealing to save his sick father. A broken soul who found purpose in love and peace… until it was all stolen from him by poison and cruelty. His transformation into a demon wasn’t a choice — it was a collapse.
When Tanjiro punches him — not slashes, not kills — just hits him with raw emotion, something breaks. Akaza remembers. He sees his fiancée. His master. The people he lost. And in a final act of penance, he destroys himself from within.
No resurrection. No redemption arc waiting in the wings. Just peace. For the first time in centuries.
Muzan’s cocoon and the calm before the bigger storm
OH MY GODDDDDDDDDD NOZOMU ABE YOU REALLY DID IT AGAIN
GYOMEI’S STONE BREATHING AGAINST MUZAN’S BLOOD DEMON ART LOOKS ABSOLUTELY INSANE MAN 😭😭😭🔥 THE INFINITY CASTLE ARC HAS OFFICIALLY BEGUN THIS WAS INSANEEEE THANK YOU GOD#鬼滅の刃 pic.twitter.com/hfDA0B0Rnc
— illegal immigrant™ 🔮 (@knyrerqx) June 30, 2024
As all of this unfolds, Muzan is still nowhere to be found. But we do know he’s curled up in the middle of the Castle like some demonic butterfly-in-progress, fighting off Tamayo’s drug and waiting for his moment to strike. The problem? The Demon Slayers can’t reach him.
Nakime continues to warp the castle at her whim, keeping everyone guessing and keeping Muzan one step ahead. It’s a fortress built on illusion and despair — and for now, it’s working.
But that’s changing. Fast.
So…who’s still alive?
SPOILER#DemonSlayer zenitsu’s 7th form reaction #sudarshan35mm. 🥵🥵💥 pic.twitter.com/Xsg72YDU8T
— RoHaN (@svsrrohan) September 12, 2025
By the end of Infinity Castle – Part 1, the body count is rising fast, but our core trio — Tanjiro, Zenitsu, and Inosuke — are still breathing. Giyu is unconscious but not dead. Kanao is fired up. The remaining Hashira are scattered and bloodied, but in the fight.
Shinobu? Gone. But not forgotten. Kaigaku? Vaporized. Akaza? Redeemed and resting in hell, finally at peace.
And Muzan? Hiding. For now.
What comes next?
THIS HOW I BE LEAVING THE THEATRE TOMORROW😭#DemonSlayerpic.twitter.com/TpnhzLsvVH
— VishalSid | CW: JJBA (@VishalSid_1) September 11, 2025
One thing is clear: this was just the beginning. Part Two promises more devastation, more showdowns, and probably a dozen more “oh hell no” moments. Kanao versus Doma is locked and loaded. The rest of the Upper Ranks are closing in. And if you thought this movie was dark? Just wait.
The Demon Slayer Corps isn’t just running out of time. They’re running out of people. But something’s shifting. Zenitsu found his god-mode. Tanjiro is reaching Hashira levels. And the momentum? It’s swinging. Barely.
The battle for Muzan’s head is no longer just a mission. It’s a blood oath. With demons dying by their own guilt, heroes turning their own deaths into weapons, and Muzan lurking just out of reach, only one question remains:
Is redemption enough to kill a demon… or just enough to make them human again?
