Thanks for your replies, but what about the hardcoded buffs that don't have tooltip and icons, like "frozen" or "drain life? Will they do the same as other empty buffs, or do the abilities using them hide them?
Anyway, the buffs I was trying to hide were from command aura (a side effect of my vampiric aura that already gives a buff), and tornado slow which gives a hero glow to non-hero models. I know I can use triggers to give that damage bonus instead of command aura, but that isn't very efficient way of doing it. And I have no idea how to make the heroglow work without tornado slow, as it changes the glow to the color of the player.