A Playable Infinity Castle, With Akaza Waiting at the Bottom
The centerpiece of the collab is a limited-time mode called Mugenjō Gekitō (無限城激闘, roughly "Infinity Castle Clash"). According to the announcement, published through PR TIMES, a Japanese press-release distribution service, players explore a 3D map modeled on the Infinity Castle, the shifting fortress where Demon Slayer's final arc takes place, and use Breathing techniques to cut down the demons in their path. Winning fights makes players stronger as the mode progresses, and the run ends at the deepest level with a showdown against Akaza.
That is an unusual setup for Knives Out, which is normally a straight battle royale: up to 100 players drop onto a map and fight until one player or squad is left standing. The mode, and the rest of the collab, runs from August 2 through September 2, 2026.
Tanjiro and Giyu Headline the Premium Gear
The spotlight items are three "Hall of Fame" pieces themed on Tanjiro Kamado and Giyu Tomioka, all carrying a "Battle of the Infinity Castle" label: a costume, the SACR-H rifle, and an EV sedan. The costume and rifle both switch between two forms representing Tanjiro's Hinokami Kagura and Giyu's Water Breathing, and the rifle mounts an exclusive 4x scope. The sedan gets the flashiest gimmick: a skill based on the Transparent World, the heightened perception state from the series, that reveals enemy vehicles within a set range and grants allies supporting effects.
There is also a collab-exclusive transport plane called "Welcome to the Infinity Castle." The plane that carries players to the battlefield at the start of each match is redesigned after the castle's tangled architecture, and every player in the lobby sees a special sequence of dropping into the Infinity Castle. Owners can also trigger a mid-flight transformation animation.
Akaza, Shinobu Kocho, and Zenitsu Agatsuma each get their own item lines. Akaza's "Return" set includes a costume, a gold-tier M4A4, and an SUV that repairs its own durability and blown tires, with the tire repair capped at twice per match. Shinobu's lineup includes an AUG, a PP2000 submachine gun, and a coupe, and her costume and the PP2000 are free for participating in collab events. Zenitsu's set is built around an SP rifle named for his Thunder Breathing, Seventh Form, plus a costume and a flight suit. Doma, Kokushibo, Muzan Kibutsuji, and Nezuko Kamado round out the lineup with further costume, weapon, and vehicle skins.
Up to 120 Free Gacha Pulls, Plus First-Collab Reruns
NetEase is handing out a lot of currency this time. Logging in on August 2 earned 10 free collab gacha pulls, and the full event stack reaches up to 120 pulls total. That includes 50 pulls for 30 days of cumulative logins (missed days can be made up later, August 2 aside, so late starters are not locked out), 10 for inviting three friends, 10 from battle pass progression, 10 from a team challenge event, and more from an exchange shop.
The non-gacha freebies are substantial too. Inviting three friends also unlocks a choice of gold-tier costume, either Shinobu or Nezuko. Upgrading the collab battle pass grants a gold-tier Zenitsu costume, the exchange shop stocks a Mitsuri Kanroji yukata outfit, and the team challenge pays out an Inosuke Hashibira "capsule car." A separate rerun banner guarantees one gold-tier item from the first collab in every 10 pulls, bringing back the Rui costume, the Inosuke bike, and the Zenitsu AWM.
Looking Ahead
The collab runs through 11:59 p.m. JST on September 2, 2026, in Knives Out, which is free to play on mobile devices. The announcement comes from the game's Japanese operation, and the release does not say whether the event will reach servers in other regions.
It lands in a busy stretch for the franchise. Japan has been airing a full rerun of ufotable's Demon Slayer TV anime since April 5, 2026, and the first Infinity Castle film arrived on Crunchyroll and digital platforms on July 28, 2026, per the official English site. Koyoharu Gotouge's original manga wrapped at 23 volumes under Shueisha with more than 220 million copies in circulation, and the complete series is available in English from Viz Media.