Q:

How does an Illusion interact with splash damage in regards to it's "x% Damage Taken" modifier?

Considering the following scenario:
The attacking hero has either Cleave (if melee) or Splash (if ranged).
The target of the attack is a hero surrounded by illusions who have a "300% damage received" modifier.
When the attacker strikes one of the illusions, does the illusion amplify the attack that strikes it, which makes the cleave/splash deal 300% damage to the by-standing hero as well, or is the damage multiplier only affecting the illusion, which means that the by-standing hero takes the normal damage?

A:

The damage taken by a target with "x% damage taken" (Illusions and victims of abilities that amplify damage such as Slardar's "Amplify") are the only ones affected by the modifier.
If someone who has 50% cleave and deals 100 damage strikes the illusion with "300% Damage Taken", the illusion will take 300 damage, and everything else around it will take 50 damage.
If someone who has 50% cleave and deals 100 damage strikes someone next to the illusion with "300% damage taken", the illusion will take 150 damage, the primary target will take 100 damage, and everyone else around it will take 50 damage.

