Mask of Madness - How does the Bonus damage recieved work?

Question

I ask about this ability: http://wiki.teamliquid.net/dota2/Mask_of_Madness Unfortunately the wiki has not alot of information about the extra damage recieved: "Bonus Damage taken: 30%"

How does this Bonus Damage work?

1. With other sources of bonus damage?
   • Additive,
   • Multiplicative?
2. Which attacks will get you extra damage?
   • Physical attacks,
   • Spells,
   • Reflect,
   • Poison damage*?
3. What kind of extra damage will it be?
   • The same kind as the attack?
   • Physical,
   • Magical,
   • "Pure Damage"*?
4. Can I reduce the extra damage?
   • Armor,
   • Magic Resist,
   • Magic Immunity
   • "Evasion"*?

Stars-Explanation:

• Poison damage: Damage Over Time
• "Pure Damge": Damage that ignores Resistances such as armor or magic resist
• "Evasion": There is on the one hand Evasion vs Physical damage against hits, and on the other hand there is atleast one Passive that I know of that has a chance to evades Spells

Answer 1

The Mask of Madness active applies a debuff which is called damage amplification. When under this status you will recieve 30% more damage from all sources except HP removal. The damage type (for the Mask of Madness) is the same as the attack itself, thus the damage can be reduced by armor/magic resistance. The damage however can not be evaded as the damage are added to the source when it hits. You can however evade (with normal evasion) the attack itself : in that case you won't undergo any bonus damage (since you don't get hit). If you are Void you even have 25% chance of backtracking magical damage. Magic amplification stack with other source of magic amplification multiplicatively.