琴古主
ことふるぬし

Translation: old koto master

Appearance: The Koto furunushi looks like a koto—a long, harp-like instrument that is the national instrument of Japan—transformed into a wild beast.

Behavior: A koto which was once played frequently but later forgotten about and stored away can transform into the koto furunushi. These yōkai may look like wild beasts, but they remember every song that was ever played on them. Koto furunushi play when no one is around, causing everyone to wonder where the music is coming from. They prefer to play old, forgotten tunes that have fallen out of style and vanished from people’s memory.