“Infinity Castle” or “Infinity Fortress” is the location of Muzan's hideout in the anime Demon Slayer (Kimetsu no Yaiba). This anime is a very popular franchise among teenagers and young people with the highest income in 2020, surpassing other well-known franchises such as Pokémon and Mickey Mouse.

As it turns out, writer and author Koyoharu Gotouge was inspired by the ryokan in the city of Aizuwakamatsu, in Fukushima prefecture, in Japan, to serve as the basis for the imaginative location or setting of “Infinity Castle” or “Infinity Fortress”.

Ryokan Ookawaso Ashinomaki Onsen

The lobby of this Ookawaso Ashinomaki Onsen ryokan is very similar to "Infinity Castle". In the lobby of this ryokan, there is a “demon Nakime” playing the harp. Ryokan Ookawaso is an inn and hot spring (onsen) located in the area of the city of Aizuwakamatsu, in Fukushima prefecture, in Japan.

Comparison with anime

In the manga Kimetsu no Yaiba, the headquarters of Muzan's main antagonist is "Infinity Fortress" or "Infinity Castle". In the image below, you can see the similarities between the lobby of the Ryokan Ookawaso Ashinomaki Onsen and the illustration in the Demon Slayer anime. “Infinity Castle” has an intricate, tiered, and dimly-lit design, and there is an area where the demon Nakime plays the harp, similar to Ryokan Ookawaso.

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