By consuming this Essence you become an essential character to your own story, protected by narrative causality itself.
*You gain impenetrable plot armor oriented towards always giving you a chance to continue living and recover from your injuries. You will never face a situation that has absolutely zero chance of survival, and narrative causality will always twist just enough to explain why your body wasn't found, or your enemy chose to capture you instead of kill you, or how you survived an otherwise lethal wound, or how your crippling injuries were eventually healed, or suchlike.
*Should you be in a situation where recovery from a certain degree of injury is impossible, you will simply avoid being that gravely injured in the first place. You can still suffer setbacks -- your plot armor will take the line of least resistance whenever possible -- but you will always eventually end up resuming your life, unimpaired.
*If you by some impossible mischance manage to overcome all of the above protections and get yourself killed anyway, you will return a while later with some kind of vague retcon for why that dead person wasn't really you or wasn't really dead.
*Should you choose to, you will not age. You will remain in the prime of life for as long as you choose to, appearing at the age you choose to. Narrative causality will guide you to an "in-setting" explanation for this if you wish, or simply have it be a thing that happens 'just because'. People will not find this odd unless you wish them to.
*You will also gain a perfect memory with infinite storage and sufficient mental adaptation to endure immortality.
*When you are finally ready to stop living and move on to what comes next, you will. This will only happen if you wish to do so while entirely in your right mind and with the utmost sincerity.