Kiva-la from Kamen Rider Decade!
I made this for fun, so it's not as gone-over as Kuuga is, nor is it properly scaled. I included a blend file with the wireframe included because of this; feel free to use that to improve the model, change the thickness of the helmet, cut out the eyes for use as PETG casting bucks, etc.
There's parts of the mouth area that aren't there. This is intentional. Slap a piece of folded-over mesh on the inside (14 count or higher plastic canvas painted black also works for this), and you'll be able to breathe while wearing it instead of suffocating.
I used the Mask Collection/マスコレ model as reference for this. They're about $10, and are amazing helmet references compared to figuarts. If you're just looking for a nice deskpiece, I'd actually recommend getting that over printing this.