Boundless Vitality

Way of Endurance: 10th level When you take damage, you can use your reaction and expend a force point to regain health equal to 1d8 + your Wisdom or Charisma modifier (your choice, minimum of one) as long as the damage would not reduce your hit points to 0. This die increases when you reach certain levels in this class: to 1d10 at 13th level, and to 1d12 at 17th level.

Granted by Way of Endurance at 10th level.