Futakuchi-Onna
A youkai woman best known for the distinctive second mouth on the back of her head—hence her name, which literally means "Two-Mouthed Woman." She's part of the Youkai Castle trio, teaming up with Tantanbou and Kamaitachi, and debuted alongside them in the Shonen Magazine story Youkai Castle.
Interestingly, the 1968 anime gave her a different name: Ooguchi-Onna (Large Mouth Woman), which is how older fans might remember her depending on which version they encountered first.
Content compiled by AnimeList.moe from publicly available sources.
