Plague Domain

Gods of plague - like Talona, Incabulos, Morgion, The Devourer, Apollo and Hel - seek to spread or prevent disease. They include gods of disease and poison, plague and famine, natural wrath and death or healing and life. In most pantheons these deities are seen as evil, spreaders of death and misery. However, some, more nature focussed pantheons see disease as a way of making way for new life. Deities of disease send their clerics to spread diseases and curses, whereas others send them to stop plagues and death. 

Cleric Level	Spells
1st	ray of sickness, detect poison and disease
3rd	lesser restoration, protection from poison
5th	bestow curse, vampiric touch
7th	aura of purity, blight
9th	cloudkill, contagion

Bonus Proficiencies

At 1st level, you gain proficiency in the poisoner's kit, heavy armor and martial weapons.

Instinctive Infection

Also at 1st level, you can spread your disease to those who would attack you. When a creature that you can see within 5 feet of you hits you with an attack, you can use your reaction to force that creature to make a Constitution saving throw. On a failed save it takes 2d6 poison damage and is poisoned for 1 minute. On a successful save the target takes half as much damage and isn't poisoned. A poisoned creature can reroll its saving throw at the end of each of its turns, ending the condition on a success.

You can use this feature a number of times equal to your proficiency bonus. You regain all expended uses when you finish a long rest.

Channel Divinity: Empowered Plague

Starting at 2nd level, you can use your Channel Divinity to increase the potency of your plague.

When you cast a spell that deals poison damage, you can use your Channel Divinity to remove any resistances or immunity the target/s have to poison damage for that instance of the spell. If the target doesn't have resistance or immunity to poison damage, it is instead made vulnerable to it.

Herd Immunity

At 6th level, you and your allies have achieved a measure of herd immunity to diseases. You gain immunity to disease, resistance to poison damage and advantage on saving throws against poison. You can also use your action to designate a number of creatures equal to your proficiency bonus within 30 feet of you. These creatures also gain this benefit.

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 to the target. When you reach 14th level, the extra damage increases to 2d8.

Increased Infectivity

At 17th level, your plague is so transmissible that any hostile creature that moves to a space within 10 feet of you or starts its turn there for the first time must make a Constitution saving throw or be poisoned for 1 minute. If a creature succeeds on its saving throw it is immune to this effect for the next 24 hours. Furthermore, you and your allies have advantage on attack rolls against creatures that are poisoned by you.