you can fight thru the greatest of pain   

When your health is reduced to 0 or below you are not conked unconcise, instead you are counted as being at Deaths Door until you are healed or killed. While at deaths door you roll death saves as normal and 3 failures will result in your character dying, any hit that connects automatically counts as 1 fail and any critical hit counts as 2 fails, any stabilizing effect that dose not normally recover consciousness such as succeeding on 3 death saves or having spare the dying cast on you will stabilize you and bring you to 1 hit point. Additionally while at deaths door you can only take 1 action, 1 bonus action or 1 movement action on a turn, you do can no longer concentrate on spells or utilize extra attacks and your movement speed is reduced to 5 feet.