While in combat with Relentless Aggression, an attack (including secondary effects such as Exhaustion & Wounds) that would normally result in death is shaken off with a tremendous effort of will and endurance that taxes the body greatly. This allows the character to keep fighting with the bare minimum Health to keep them conscious and active.
1/Long Rest Cycle per Measure; When the character is reduced to 0 hit points but not killed outright, they can drop to 1 hit point instead.