Pure Soul

You can increase your constitution or your wisdom by 1.

Bad experience with death made you in strong communion with your own soul. When your body become weak, your strong soul seems to protect your existence.

When you're below half of your hit points or below 40 hit points (lowest between the two) , every first damage you receive this round is reduce by half your level (rounded down, but minimum of 1).

You also need to fail 4 death saves to die permanently, as if your soul don't want to leave your body.(Ignore the first fail in your death saves).