There's a lot of things that could be said about these pictures of this character. To start, it's not new to create a character based only on a pixel. But his time this character will probably be introduced with a name and picture in the game. Seeing these rushed pictures seems so... dunno, weird, just weird.
For all that we know it's Cirno. Yeah, Cirno. Powers are acting weird, this is part of the story that's been posted. There's no Master Spark because of that, but Dark Spark. Some characters can't use their powers fully and others just can't use them. So, and with the name of the game in mind, that unnamed character can just be a negative palete swap of another character, a "dark" version of a character.

Not enough frills and modest head dress points toward a very early boss stage.

pt_kamen said:

For all that we know it's Cirno. Yeah, Cirno. Powers are acting weird, this is part of the story that's been posted. There's no Master Spark because of that, but Dark Spark. Some characters can't use their powers fully and others just can't use them. So, and with the name of the game in mind, that unnamed character can just be a negative palete swap of another character, a "dark" version of a character.

Where have you read this? TH wiki says only that Reimu's, Sakuya's and Marisa's weapons are acting weird, and that "various youkai bagan to rebel".

pt_kamen said:
There's a lot of things that could be said about these pictures of this character. To start, it's not new to create a character based only on a pixel. But his time this character will probably be introduced with a name and picture in the game. Seeing these rushed pictures seems so... dunno, weird, just weird.
For all that we know it's Cirno. Yeah, Cirno. Powers are acting weird, this is part of the story that's been posted. There's no Master Spark because of that, but Dark Spark. Some characters can't use their powers fully and others just can't use them. So, and with the name of the game in mind, that unnamed character can just be a negative palete swap of another character, a "dark" version of a character.

If that is the case, then almost all the bosses in this game would be returning bosses, and it's not like the series to reuse several bosses in a single game.

This makes me think of those inventive pictures people drew of "Nazrin" before UFO came out. I wonder if we have any of those up here on Danbooru.

I'd be surprised if this character would be human... :3