Razors that look to be made of some sky blue glass. They attach a blue edge to the blade.
Swinging with this sends forward an arch of wind (or at least wind particles) that can damage enemies it hits, having a small chance to knock them back, dealing more damage if they are knocked into a wall.
Think of the crystal enemies from the mines, it would be a similar attack, maybe with the same effects to at least serve as a placeholder for testing.
Thoughts?