Boarish Resilience (5e Feat)
From D&D Wiki
Prerequisites: Shifter (Beasthide)
Your lycanthrope ancestry has lead to you having powerful fortitude, even at death's door.
- Increase your Constitution by 1, up to a maximum of 20.
- When you are reduced to 0 Hit Points but not killed outright, you can drop to 1 hit point instead. The damage can't be more than half your hit point maximum. You can’t use this feature again until you finish a Long Rest.