Damage Types

Damage Types

Hey, I was looking through the triggers, and this question has prodded me for a while.
When you have the trigger Order unit to damage target,
I know what attack type is (chaos, spells, piercing, normal) but what is damage type?
What is the difference between

• Normal
  
• Unknown
  
• Plant
  
• Shadow Strike
  
• Lightning
  
• Enhanced
  
• Sonic
  
• Acid
  
• Divine
  
• Death
  
• Disease
  
• Cold
  
• Fire
  
• Mind
  
• Defensive
  
• Demolition
  
• Poison
  
• Slow Poison
  
• Spirit Link
  
• Universal
  

Are they just for more triggers, like

If
Damage type was equal to cold
Then do
Kill Unit
Else
Do Nothing

Or is there some otherworldly point to them?
--donut3.5--

I would like to know this as well.

as far as i know, Magic Immunity blocks Universal, and thats it