Detail this asset from Unity Store: Original Link
This is a paid asset, but now you can download Floating Embers VFX Free.
Floating Embers VFX v1.1
A collection of, burning embers particle systems, ready to drop into any scene.
There are three prefab particle systems. Slow floating, medium and fast moving.
The ember particles are each an animated texture sheet to add to realism and make the systems look much more interesting.
Particle count is low and so work perfectly on mobile as well as desktop and console.
NOTE: Includes my Particle Scaler Utility