Final answer:
Relentless Rage is a survival feature that allows a barbarian to avoid being reduced to 0 hit points by making a Constitution saving throw, showcasing their resilience and survival capabilities in combat.
Step-by-step explanation:
The ability Relentless Rage grants a barbarian in the role-playing game Dungeons & Dragons an impressive survival mechanism. Once a barbarian reaches 11th level, they can utilize Relentless Rage when they are reduced to 0 hit points but not killed outright. Instead of going unconscious, the barbarian can make a DC 10 Constitution saving throw to instead drop to 1 hit point. The feature showcases the sheer resilience and survival instinct of barbarians. However, it's important to note that each subsequent time the barbarian uses this feature before a rest increases the DC by 5, making it harder to succeed. This ability is integral in helping the barbarian stay in the fight longer, protecting allies and continuing to deal damage.