there a couple of textures featuring Nini-tan/Sakura (Ukagaka's first default ghost) hidden inside the game files for Ys VI: The Ark of Napishtim (Windows)(2003) and Ys: The Oath in Felghana (Windows) (2005) developed by Nihon Falcom.
the test map tiles featuring Nini-tan titled TEST1-1.png and TEST2.png were found in a folder titled 'hidden'.
in The Ark of Naphishtim the texture is featured on the walls of 2 unused maps, S_HIDDEN0 and S_HIDDEN2. the maps lack proper boundaries
in Oath of Felghana it's used again in (a slightly different) unused debug map, S_HIDDEN0
they're probably not intended to be seen during normal gameplay, presumably put there at some point by a developer who uses Ukagaka as placeholders for debugging purposes and leftover in later Windows Ys games from Ys VI. the rooms remain in Ys Origin but with the Nini/Sakura image removed.
source: (★) , (★), (★) (initially discovered by 'koa' from the Ancient Ys Forums back in 2009)
