Resolved Fighter (5e Feat)
From D&D Wiki
Prerequisites: Wisdom 13 or higher
Thanks to your willpower, your body can surpass its limits, allowing you to survive adversity.
- When your drop below half of your hit point maximum, you gain temporary hit points equal to your level for 1 minute. You regain use of this feature after you finish a short or long rest.
- When you are below half your hit point maximum, you gain a +1 bonus to your AC.