>>48575028>1 is possibly a dark type froslassNah. For one, Froslass is a Pokemon that was introduced in Sinnoh originally, there'd be no point to making a Hisuian version. Plus, it wouldn't be much of a riddle, since that girl looks so much like Froslass to begin with.
>1. A Yokai from Yokai Watch, her Japanese name is the key, once you know it, you will understand all abt this mon.That Yokai is called Damona, and her name in Japanese is Hyakki-hime. This translates to 'hundred demon princess'. This would seem to point towards Spiritomb.
I know this contradicts the point I made with Froslass above, but I feel that if there were any one Sinnoh Pokemon that would make sense to have a Hisuian form, it'd be Spiritomb. Maybe some kind of 'unsealed' variant?