Here is one example how to remove particlesemiters from Doom Guard
now I will remove the weapon first
And you see the flame where was his weapon
To remove the particles (Flame) you need to convert the model in MDL
and simple open it in Notepad
Now press CTRL+ F and search
You will find there 4 ParticleEmitters
Select the 4 ParticleEmitters and remove them like a simple text, but be careful
if you make a mistake you can't undo 2 times
Now if you remove the ParticleEmitters text you will get this
Save the file, close the notepad.
open the Doom Guard in War3 Model Editor
I think I helped you