This is wrong. Chaos damage is reduced by armor like any other attack type.if you want to deal full damage nomatter the amount of the armor the target has, you should use chaos damage as damage type as it goes through all types of armor (i think)
I did thisif you use some uber crazy complicated own damage system you might use "unit - damage target" and use the damage type "unknown" since this will ignore armor values.
if you want to deal full damage nomatter the amount of the armor the target has, you should use chaos damage as damage type as it goes through all types of armor (i think)