This game has a number of unreachable effects and characters that might be implemented in its future releases. They are merely at their development stage. These are their sprites found in the game files.
Nakitsuki - Melon (メロン)
Niyatsuki - Shinto Priest/Kannushi (かんぬし)
Niyatsuki - Doctor (いしゃ)
Nakitsuki with messy hair.
Red Crayon (クレヨン赤) - a debug room only character that is planned to be implemented in the game's future releases.
Atatsuki (あたつき) - a placeholder for enemies in the MonsterData folder. Not implemented.