Dark Priest

You were once a devote believer but, for some reason, you changed. Maybe it was your thirst for forbidden knowledge... or maybe the regret for not being able to save your party? Either way you reached to some unholy deity seeking more power, and it was granted to you... at a price.

Dark Priest Spells

Cleric Level	Spells
1st	Fog Cloud, Healing Word, Hellish Rebuke
3rd	Blindness/Deafness, Darkness
5th	Mass Healing Word, Bestow Curse
7th	Blight, Phantasmal Killer
9th	Contagion, Cloudkill

Unholy power

When you choose this domain 1st level, you lose your power to heal others. Every time a spell or ability you use would heal or give temporary hit points to a creature, it deals the the same amount as damage instead. If the spell has self as target, it becomes touch. If the spell is an area of effect, you are immune from it. Every time you damage a creature in this way it gains a stack of unholiness (they lasts for 1 hour unless consumed by other abilities)

Soul offering

From 1st level, whenever you are within 10-feet radius when an enemy is killed, you can choose to use your reaction to offer that creature soul as an offering. If you do, you are healed by Xd4 where X equals the stacks of unholiness on the enemy killed (up to a maximum of 5). You can choose to spread the healing with your nearby allies (within 30-feet radius). This ability is not affected by Unholy Power. The heal you receive is increased to Xd6 at level 9.

Channel Divinity: Despair

Starting at 2nd level, you can use your Channel Divinity to throw your enemies into despair. As a bonus action you can choose a creature with at least one stack of unholiness and make it fall into despair. While a creature is in a state of despair you cannot apply any more stacks of unholiness to it. Also you can consume one or more stacks of unholiness to apply any of the following effects at any time.

Wither away (consumes 1 stack)

The creature feels as if they're withering away, it will have disadvantage in 1 saving throw of your choice until the end of your next turn. This effect cannot stack

Steal senses (consumes 2 stacks)

The creature is affected by the spell Blindness/Deafness. It will automatically fail the initial saving throw

Dark binding (consumes 1 stack)

The creature is unable to make any movement until the end of your next turn.

Explosion (consumes 5 stacks)

An explosion of darkness originates form the creature. Every creature within 10 feet from it must make a DEX saving throw (DC 15). Each creature takes  2d10 force damage and is knocked prone on a failed saving throw, and half as much damage and is not knocked prone on a successful one.

Corruption

At 6th level you can intercept and corrupt any kind of healing. When a creature within 30 feet from you is being healed you can use your reaction to reduce the healing by 2d6 + your spellcasting modifier. If you reduce the healing to 0 you can choose to corrupt it instead. When you do so the spell will be affected by your Unholy power as if you were the one casting it. the healing reduction is increased to 3d6 + your spellcasting modifier when you reach level 11 and 3d8 + your spellcasting modifier when you reach level 14

Cursed wounds

Starting at 8th level you can target any creature within 300-feet radius with one or more unholiness stacks. When you do, the creature must make a CON saving throw with DC equals to 10 + your proficiency bonus + your spellcasting modifier. On a failed check the creature is cursed and its current HP become its maximum HP and its wounds will not heal anymore. A creature afflicted with this curse will likely realize it after a few days or when they attempt to heal the wounds through magic. This condition can only be removed by Remove Curse or similar spells. You can only use this ability once every long rest.

Life Tribute

Starting at level 17th, you can tribute your own life force to enhance your allies attacks. As a reaction when a friendly creature makes an attack roll, you can expend a maximum of 5 hit points to increase the result by the same amount. You can do so until after you see the result of the roll, but must decide before the DM says whether the roll succeeds or fails. If there is a creature affected by your Channel Divinity: Despair, you can instead choose to consume a stack of unholiness to drain the required life from that creature.