Celestial Boon: Greater Blessing of the Guardian Angel

Very rare boon 

You are watched by a powerful divine protector.

• When you would die due to a failed death saving throw, you instead regain hit points equal to 5 times half your level, rounded up.
• If you would fail your saving throw against a spell or effect that causes instant death, you can reroll that save with advantage.

Once either of these effects have been used, they can’t be used again until you finish a long rest and spend at least an hour praying or giving thanks.