Frenzied Berserker Utility 12Deathless Frenzy

For a time, your anger can stave off even death.

Daily        Primal
Immediate Interrupt      Personal

Trigger: You drop to 0 hit points or fewer and don’t die

Effect: Until you regain hit points, you are dying but don’t fall unconscious because of that condition. If you fail a death saving throw, you fall unconscious, and this effect ends.

Published in Player's Handbook 2, page(s) 64.