Clerics who vow to the Peril domain do so with the focus of helping others see the value of life. They seek to bring others closer to death, but to ultimately keep them from tipping over the edge into the abyss. Such practices often come with a stigma, as do all whose worship brings them close to the domain of death.

Source: I Made It the Fuck Up

Peril Domain Spells
Cleric Level Spells
1st Cure Wounds, Sanctuary
3rd Gentle Repose, Safeguard Existence
5th Vampiric Touch, Revivify
7th Aura of Life, Death Ward
9th Mass Cure Wounds, Raise Dead

Mortally Empowered

At 1st level, you have learned to use the difference between life and death as a tool. You have a pool of Mortality points equal to your cleric level which you can spend for various effects, as listed below. Your pool of Mortality points resets when you finish a long rest.

  • Terminal Velocity. If a creature you can see is below half of their maximum hit points at the start of their turn, you may spend a number of Mortality points up to half your cleric level (to a minimum of one). Until the end of their turn, that creature adds 5 feet to their speed for each Mortality point spent.
  • Back From The Brink. After a creature you can see makes a death saving throw, you may spend any number of Mortality points to add a bonus to the roll equal to the amount spent. You must use this feature before the death saving throw is rolled. If the roll result is greater than 20, the creature gains hit points equal to the difference. If the unmodified roll is a 1, this effect is ignored and the creature still suffers two failures as even the most careful practitioner can encounter unexpected dangers.
  • Reprieve. When a creature is healed by you, you may spend Mortality points up to the amount of hit points healed. The affected creature then gains temporary hit points equal to the amount of Mortality points spent.

Dangerous Endeavor

Also at 1st level, as an action, you can bring one of your allies to a state of continued peril, and harvest this energy to replenish your Mortality points. Choose a willing creature within 5 feet of you, if that creature’s hit points are above 3/4 of their hit point maximum (rounded down), their hit points are reduced to 3/4 of their maximum and their hit point maximum is reduced by an equal amount. That creature gains temporary hit points equal to the amount lost, and you gain an equal number of Mortality points. Each creature can only be affected by this feature once per long rest. When the creature finishes a long rest, their maximum hit points are restored to normal.

Channel Divinity: Gasping Doom

At 2nd level, as an action, you can present your holy symbol and instill an overwhelming sense of impending doom in the creatures around you. Each creature of your choosing with an Intelligence score of 4 or higher, that can see you, and that is within 30 feet of you must make a Wisdom saving throw vs your spell save DC. If a creature fails the saving throw it is frightened of you and begins to suffocate. At the beginning of their turn, affected creatures can repeat the saving throw, ending these effects on a success.

Creatures that cannot be frightened or that do not need to breathe are immune to this effect. Additionally, this effect ends when an affected creature is more than 30 feet from you.

Death Denied

At 6th level, as a reaction, when a creature you can see within 60 feet of you drops to 0 hit points, you may have their hit points become 1 instead. When you do this you begin to Concentrate as though you would a spell, but this effect does not count against the number of spells you may Concentrate on. You still are required to make Concentration checks for this effect when you normally would be required to do so. You may only Concentrate on this effect for 1 creature at a time.

While you are Concentrating on this effect, that creature can neither gain nor lose hit points. When the affected creature takes damage you must make a Concentration check for this effect. Determine the DC for that check as though that damage had been dealt to you.

When you lose or end Concentration, that creature’s hit points return to 0 and the creature becomes unconscious. You may stop Concentrating on this effect at any time.

Peril’s Reward

At 8th level, as an action, you can beseech your divine patron to reward those around you who have suffered from being in a dangerous situation. When you do so, choose a number of creatures up to the value of your Wisdom modifier that you can see, to a minimum of 1. Those creatures gain benefits according to the table below for the next minute.

These benefits are cumulative based on the amount of hit points they possess in comparison to their hit point maximum.

Benefits are lost or gained as the creature’s hit points change.

Rewards
HP Effect
<50% At the start of the creature’s turn, they may gain 1 point of Peril. These points are lost if the creature's hit points drop to 0.
<10% When the creature is healed, they heal an additional d6 for each point of Peril they have, and lose all of their Peril points.
1 The creature makes saving throws with advantage and all effects that restore hit points use the maximum number possible for each dice rolled. Spells you cast that heal the creature are considered to have been cast with a spell slot 2 levels higher than was actually spent to cast the spell when determining the spell’s effect for the creature.

You may use this feature a number of times equal to your Wisdom modifier, to a minimum of one. You regain all uses when you complete a long rest.

In addition, if your current hit points are below 50% of your hit point maximum, when you hit a creature with a weapon attack you can cause the attack to deal an extra 1d8 necrotic damage to the target. When you reach 14th level, the extra damage increases to 2d8.

Master of the End

Starting at 17th level, any damage you suffer that would take you below 1 hit point may instead be subtracted from your Mortality points. While you have exactly 1 hit point, you have resistance to all damage.

In addition, attacks against you cannot score a critical hit while you are unconscious.