Let's say Hawkeye hit Ares with EE and armor piercing... Ragman happens to be next to Ares and takes the Splash damage.

??? Do I take a click from each Mystic... or just 1 click from Ares ???

Just one.

~Phil

Edit: Post after is right, this is not.

You would take 2 damage.

Mystics triggers when the Mystic TAKES damage from an ATTACK. The splash damage taken by Ragman is an attack.