Yonigamisama

Nijino and Rumi are cousins. They came to the village in the mountain for their grand-aunt's memorial service.
The mysterious folklore, something that even the villagers had forgotten, was starting to surface from the depth. A ghost, Yonigami, was known to kidnap young girls in order to plant his "seed".
Nijino and Rumi became captives of the men wearing creepy masks. The girls were sinking into the bottom of their nightmare, being attacked.
Eventually, unknown grotesque new lives began to grow inside the girls' bodies.

Released at Comiket 72 in August 2007.
Short gothic novel with a mini CG image collection.

God or Demon
Old Yonigami-sama who controls the mountain was making an appearance after 99 years...