I made this for fun (a while ago) when I was testing out some of the new features in 2.9. I pulled in the upper body from an unfinished project and then added the mask and horns, etc. I really love volumetrics in Eeevee because you can make the viewer think that something is there but not have it there at all (as shown in the next picture). I rendered this in Eeevee, and did all the compositing in Blender.
I used a subdivided cube with a curve modifier for particle systems which seemed to work really well. I don’t know if other people do that, but I really recommend it!
Feedback is welcome! Enjoy!