Plague Domain

Filthy, ragged, and foul smelling. Clerics of Plague seek to spread death and disease in order re-balance nature. They worship the natural processes of rot and decay and might find divine beauty in a bloated corpse or mushroom covered log. They infect others, and often themselves, with illness as a form of prayer; endlessly seeking worse diseases as tribute to their dark gods.

Bonus Proficiency

When you choose this domain at 1st level, you gain proficiency with martial weapons and alchemist's supplies.

Warped Healing

Also starting at 1st level, you are able to warp spells of healing to attack your enemies. You may choose to cast a corrupted form of one of your healing spells against a creature. The target must succeed on a Wisdom saving throw or take poison damage equal to twice the amount the spell would usually heal and be poisoned. At the end of each of its turns, the target can make another Wisdom saving throw. On a success, the effect ends.  This feature doubles the amount of dice usually rolled for the healing spell, but does not allow you to add your spell casting modifier twice. All other feature of the spell are the same

Channel Divinity: Spread Plauge

Starting at 2nd level, you can use your Channel Divinity spread a dangerous disease.

As an action, you can use Channel Divinity to attempt to infect a number of creatures of your choice equal to or less than your Wisdom modifier (but not less than one) within 60 ft. with a wasting disease. Each target must make a constitution saving throw against your spell save DC or be infected.This disease causes an infected creature to become vulnerable to poison damage and to become contagious after 1d4 days. Once contagious a creature will infect any other creature with which it shares bodily fluids and will have its maximum hit points decreased by 1 ever hour. If this effect causes a creature to reach zero hit points the creature will die. This can be cured by any effect which cures disease such as a potion or spell.

Priest of Decay

Beginning at 6th level, your knowledge of rot and decay allows you to inflict additional damage with your spells.. When you cast a spell of 1st level or higher that deals necrotic or poison damage, you can add damage of that type equal to 3 + the spell’s level.

Pestilent Strike

At 8th level, you gain the ability to infuse your weapon strikes with corpulent 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 to the target. When you reach 14th level, the extra damage increases to 2d8.

Lord of Decay

Starting at 17th level, you gain an resistance to necrotic damage as well as immunity to poison damage and the poisoned condition. Additionally, when you cast a spell that deals either of these types of damage you may make a melee attack as a bonus action.