Nakime is a character from Demon Slayer whose biwa playing is tied to the Infinity Castle and its shifting rooms. Online, this short biwa sting became a recognizable anime audio for eerie transitions, teleport-like scene changes, and villain-focused edits. It is especially common in fan edits on short-form video platforms, where a single pluck can signal that the space is changing or that something ominous is about to happen. Its staying power comes from how quickly it establishes tension in less than two seconds.