Die Hard

You are extremely difficult to kill, even after you have fallen in battle. You gain the following benefits:

• Increase your Constitution score by 1, to a maximum of 20.
• When you are reduced to 0 hit points and don't die outright, you are stable. If you take damage thereafter, you become unstable and begin making death saving throws as normal.
• While you are at 0 hit points, critical hits against you only incur one death saving throw rather than two.
• You become stable after succeeding on two death saving throws rather than three.