Cult Domain Edit
The Cult domain is for a cleric that was not from an orthodox religion, instead of worshiping deities, they worshiped a powerful being; an otherworldly patron. They are similar to a warlock, but they are not quite the same.
Cult Domain Spells Edit
Choose a Warlock Otherworldly Patron. You gain the spells from it's list at the regular cleric domain levels (1st 3rd 5th 7th 9th), and they are always prepared for you.
Bonus Cantrip Edit
When you choose this domain at 1st level, you gain a cantrip of your choice from the warlock spell list.
Eldritch Invocations Edit
Also starting at 1st level, you gain a single Eldritch Invocation from the warlock class of your choice. You gain additional invocations at 6th, 8th and 17th levels, and each time you gain a level in the cleric class, you may replace one invocation with another one you meet the requirements for. You replace any features requiring your warlock level with your cleric level, and your Charisma modifier with your Wisdom modifier.
Channel Divinity: Patron Spellcast Edit
Starting at 2nd level, you may choose to cast a spell from your Otherwordly Patron. Doing so in this way adds your Wisdom modifier to the damage roll of the spell (if any), and casts it at one level higher than it's lowest slot.
Patron's Minor Blessing Edit
Beginning at 6th level, your patron bestows upon you a small blessing. You receive the 1st level warlock feature of your patron. (e.g. Dark One's Blessing for Fiend Patron) You replace any features requiring your warlock level with your cleric level, and your Charisma modifier with your Wisdom modifier.
Potent Spellcasting Edit
Starting at 8th level, you add your Wisdom modifier to the damage you deal with any cleric cantrip.
Boon of the Patron Edit
Starting at 17th level, you gain a Pact Boon from the warlock class. Additionally, you gain the lowest-level required invocation for that pact boon, without taking up an invocation slot.