Unyielding

You have the strength to overcome the mightiest foes and have the fortitude to keep standing in the most exhausting fights. When you would normally drop to 0 hit points, you can make a DC 10 Constitution saving throw to instead drop to 1 hit point. You cannot do this again until an hour later. If this attack would reduce you to your hit point negative, you can make a DC 25 Constitution saving throw to instead drop to 0 hit points and begin making death saving throws.