The magic system in Heroes V [Discussion]

So, what's the difference between Blind and Weakness? The stack still moves, but it deals less damage. And this is the effect of the Weakness spell:confused:

If a regular curse reduces the damage of each unit in the stack, now it reduces the number of creatures dealing damage.

How did he calculate that? Does it say that 10 out of 100 hit? And how does this curse disable part of the units?:eek: Do they go for a beer or something? :)
I wonder if Dispel also removes negative effects in the same way. Does it affect only part of the units, while others remain unaffected? And how does the stack move then:eek: