Kotobuki (1997)

The lead characters from C's Ware's hentai games grew tired of constantly being forced to act in pornographic scenes. They joined forces and created an artificial realm called the "C's Ware Land". They also swore that no hentai player shall ever use them again for their dubious purposes. However, two characters that never made it to any C's Ware game - the boy Pao and the girl Pino - decided to venture into the dangerous land and defeat the former protagonists.