Diseases have long been seen as one of the most fundamental enemies of civilization: an impartial force of death and suffering, plagues can rip through the fabric of cultures and bring even the most mighty of empires to its knees. Universally feared and actively avoided, there are yet some who embrace the power of pestilence as the greatest equalizer of the living and the most aggressive tutor to prideful nations. Those who draw on the supernatural capacities of those who condone and create diseases may still see value in healing others of their pains and plagues, but such cures often carry a price or consequence that extends the lifespan of the original harm.

Plague Domain Spells
1st - Inflict Wounds, Ray of Sickness
3rd - Lesser Restoration, Ray of Enfeeblement
5th - Bestow Curse, Blackened Heart
7th - Blight, Sickening Radiance
9th - Cloudkill, Contagion

Bonus Proficiency
At 1st level, you gain proficiency with martial weapons and heavy armor.

Plague Priest
From 1st level, your god enables you to manifest its energies in a variety of ways. When you cast a spell that deals radiant, necrotic, or poison damage, you can change the damage type to another on this list. When you do so, creatures with advantage on saving throws to resist poison, or creatures immune to poison damage, gain advantage on any saving throw associated with the spell cast in addition to any normal resistances or immunities to the new damage type.

Heart of Disease
Also at 1st level, you gain resistance to poison damage and gain advantage on saving throws to resist a poison's affect.

Channel Divinity: Influence of Pestilence
Starting at 2nd level, you can use your Channel Divinity feature to warp the nature of poisons and diseases.

As an action, you present your holy symbol and invoke the name of your deity. For one minute, each creature you can see within 30 feet of you either gains resistance to poison damage, or loses their resistance to poison damage. Creatures who were immune to poison damage become resistant to that damage instead and lose any immunity to the poisoned condition that they might have.

Corroded Blood
By 6th level, your deity grants you further defenses against the forces it governs. You gain immunity to diseases and both the charmed and feared conditions, and when you are subjected to a poisonous effect that allows you to make a Saving Throw to take only half damage, you instead take no damage if you succeed on the saving throw, and only half damage if you fail.

Divine Strike
At 8th level, you gain the ability to infuse your weapon strikes with divine energy. Once on each of your turns when you hit a creature with a weapon attack, you can cause the attack to deal an extra 1d8 poison damage or the damage of the same type dealt by the weapon to the target. When you reach 14th level, the extra damage increases to 2d8.

Pandemic
Upon reaching 17th level, your Influence of Pestilence Channel Divinity feature gains two of the following properties for its duration:
• you may choose to invoke the feature as a bonus action instead of an action on your turn.
• allied creatures that you make resistant to poison damage are instantly cured of all poisons and diseases affecting them and gain immunity to the poisoned condition.
• hostile creatures take poison damage equal to your Spellcasting Ability Modifier at the start of each of their turns.
• hostile creatures that were not initially resistant or immune to poison damage become vulnerable to poison damage.