Some TMNT stuff really isn't for little kids.
Vulvana is one of the original fallen angels who was cast out after failing to overthrow The Creator. She now resides in Yomi, the Japanese underworld, in charge of the gateways between Earth and the underworld.
In Fox Hunt, Raphael, Ninjara, Naga, and the latter two's grandmother flee from a big game hunter through a torii leading them to Yomi, where they encounter Vulvana. Vulvana cannot leave Yomi, so when mortals cross over into her world, she gives them a test of purity in order to allow them to pass. The hunter fails and is cast down into Hell, but the four anthromorphs make it back through the torii and their world.
- Vulvana's name is a play on the word vulva.