Anime “Demon Slayer: Kimetsu no Yaiba” is partnering with Hakone Kowakien Yunessun for a limited-time collaboration event titled “Kimetsu no Yaiba × Yunessun: Hakone Onsen Tan ~Wisteria Flower Rest~,” running from July 18 to October 4, 2026. The adjacent official hotel, Hakone Hotel Kowakien, will also feature special collaboration content.
“Demon Slayer” is based on the manga by Koyoharu Gotoge, serialized in Shueisha’s Jump Comics with over 220 million copies in circulation. The anime adaptation by ufotable began in April 2019 with the “Tanjiro Kamado, Unwavering Resolve Arc.” The final battle arc set in the Infinity Castle is being produced as a film trilogy. The first chapter, “Infinity Castle: First Chapter – Akaza’s Return,” was released on July 18, 2025. As of April 9, it had attracted 27,455,968 viewers and grossed over 40.2 billion yen, making it the second highest-grossing film in Japanese history, following the previous film “Mugen Train.”
Limited-edition collaboration tickets are currently available for purchase. Each ticket includes original goods featuring a ufotable illustration of five characters enjoying Hakone Kowakien.
Themed Baths and Sauna at Yunessun
Yunessun, a water park where guests bathe in swimwear, will offer two collaboration baths: the “Wisteria Flower Bath” and the “Infinity Castle Bath.” The wisteria-decorated “Wisteria Flower Bath” lets guests soak surrounded by the Demon Slayer Corps. The collaboration sauna, “Wisteria Flower Steam Bath,” will host daily sauna events called “Special Training” led by Yunesse Masters. Participants can experience a “flashy and heart-body warming” löyly (aufguss) while being watched over by Sound Hashira Uzui Tengen and Flame Hashira Rengoku Kyojuro.
The “Infinity Castle Bath” is inspired by the film “Infinity Castle: First Chapter,” recreating the fierce battle between protagonist Tanjiro Kamado, Water Hashira Giyu Tomioka, and Upper Moon Three Akaza.
Exclusive Collaboration Room at Hakone Hotel Kowakien
At the official hotel Hakone Hotel Kowakien, a special “Demon Slayer Room” will debut—the hotel’s first collaboration room since it opened in July 2023. The interior is adorned with iconic scenes from the anime and films, making it a must-see for fans.
The collaboration event “Kimetsu no Yaiba × Yunessun: Hakone Onsen Tan ~Wisteria Flower Rest~” runs from July 18 to October 4, 2026.
