When you are reduced to 0 Hit Points, you begin to Bleed Out.
While you are Bleeding Out, you must lie on the ground and can take no action other than to speak/yell (you can always scream for help while you’re Bleeding Out). You cannot drink a potion, use any character abilities, cast any spells, activate magic items, or otherwise take actions to save yourself. The only exception to this is the Unstoppable Force ability, which lets you recover +2 Hit Points immediately after you are reduced to 0 Hit Points.
If the terrain you are in when you are reduced to 0 Hit Points is too dangerous to lie on the ground, you can take a few steps (without taking any other actions such as attacking, casting a spell, or drinking a potion) to move to a safer location. If moving to a safer location is unfeasible, you can instead take a knee and place both of your hands on the ground, calling out “Bleeding!” to alert any attackers to the fact that you’re Bleeding Out and not kneeling for some other reason.
While you are Bleeding Out, start tracking the elapsed time; if you are not healed within a certain duration, called your Bleed Timer, your character dies. See the Death & Respawn page for details on how that works.
If you are healed for any amount of Hit Points before you die, you stop Bleeding Out and can once more stand up and take actions normally.
Your Bleed Timer is how long you have to live after you are reduced to 0 Hit Points and start Bleeding Out. When your Bleed Timer expires, you die, and travel back to the borders of Veilguard to Respawn.
Your base Bleed Timer is 2 minutes, or 120 seconds.
While you are suffering from the Envenomed condition, your Bleed Timer is reduced to 1/6th its normal duration (or 20 seconds for a base Bleed Timer).
The Vigor ability increases your Bleed Timer by a set amount for every level of it you take. Other effects such as the Clotting Elixir or some enchanted items can also increase it. All of these effects stack with each other.
If another character begins performing a healing spell or ability on you, your Bleed Timer is paused while they are doing so. If they are interrupted or for some reason are unable to heal you, your Bleed Timer resumes its progress.