Hi everyone . I'd like to talk about an idea for a game. Alright let's get started.
There is this beautiful girl named Yukiame Misutikku. She (as the title implies) is an Yuki-Onna
but, prefers to hide it form people wait, as a matter of fact, she has to hide her race beacause
of the way Yuki-Onna are treated her country.(Freene) Yuki-Onna, as depicted in history, are
ghostly beautiful spirits who are ruthless killers. Some stories say they cause people to freeze
to death and tears the livers out of living children. In other stories she can pull out your soul and
she calls out to passers-by and pushes them into ravines if she is ignored. Despite all these stories,
the Yuki-Onna of Freene are very beautiful, charming, and gentle women who have the power to
manipulate the element of ice. Also, they are a race instead of the spirits of deceased women.
Anyways, the humans of Freene still stick to the old stories and still think of Yuki-Onna as "cold
blooded" killers and are planning something to get rid of them. The humans tell King Kasai, a
descendant of Hinokami, prepares a mass genocide of the Yuki Onna.

Do it

It's a cool idea (no pun intended), but I just think you need to organize your story, and make it a story to begin with. So the humans are preparing a genocide for all Yuki-Onna, how does your character find out about this? What's the conflict?

Consider how your gameplay revolves around this story, too. Making it a plain RPG would be fine, but it would also be a bit forgettable in that regard. Having her magic spells revolve around ice, or using freezing powers to solve puzzles in dungeons or whatever can be an example of how you can do this. Keep developing this idea.