Originally titled “Faradoon: The Legend of Dragon Castle”, Monika No Shiro (Monika’s Castle) is a cancelled RPG that was in development for the Sega Saturn in 1996 / 1997, by Pioneer LDC. The game could have been almost completed, as they had a final box art and various ads on magazines, but for some reasons it was never released in the end.
It seems that a playable demo of Monika No Shiro was available at the Tokyo Game Show 1997 (?). Thanks to Raizing from Sega Saturno we can take a look at a trailer and many images from the game! You can find more info on the game (in spanish) in the Sega Saturno Forum.
Thanks to Celine for the contribution and to Rod_Wod for one of the scans!