In this case it's not RPG at all (I know there is no EXP or level there). It's an adventure with puzzle elements.
I think this misconception stems from the developers calling it an RPG in Japanese press of the game.
You do (sort of) control levels of three different evils that act sort of like the overloading bar in Galerians or Dragon Counter in BOFV Dragon Quarter. If you don't keep the levels under control, you can get a game over from any one of them maxing out. However, it's particularly hard and time-consuming to even do this, so the whole feature goes largely unnoticed unless players go out of their way to max out.
There are very few rewards for dogging the evil meters, but controlling the evil meters to manage which characters appear when and where does give extra layers to the game's story, and might give some players a little replay value. To that end, it could count as an RPG.