Yeah, however, isn't it kinda mean to have void flames as they're not transparent? So usually, when I fighting a guy with void flames (unless they're really small), I have to /opt particles 0, so his void doens't mess up my vision. However, if he uses purple flames, I can see through them and vision is not a problem.
Even with fancy color particle, center of void flames is not transparent... So they're either to watch as a spectator or for singleplayer, not for playing with them or vs them (since the vision problem).