Unbreakable
Fighter Utility 6
Encounter ✦ martial
Trigger: You are hit and damaged by an attack.
Effect: The damage is reduced by 5 + your constitution modifier.
Unbreakable is a level 6 fighter utility power. [PH:80][Dr398:CC]
It is an average choice, as the damage reduction is nice but burns the immediate action and doesn't scale. [1]