The powers demonstrated by atheist clerics are a great source of mystery. That clerics are empowered with divine magic by their subject of worship (be it a god, fiend, extra-planar entity, or even a mere shared ideal) has been fact for millennia, and yet atheists seem able to wield divine magic while explicitly denying the existence of higher powers. There are a variety of theories that attempt to resolve this apparent paradox. Some say they're simply confused sorcerers. Some say they're servants of a hidden god seeking to weaken its competition. Some say they harness an exotic "antidivine force" from the outer plane. Some even dismiss them as con artists. As rare as atheists are, however, not one of these theorists has ever collected enough evidence to put an end to the mystery once and for all.

Mind of Steel

When you choose to become an atheist at 1st level, you may gain proficiency in Religion or Persuasion. You also become proficient in your choice of one of the following skills: Religion, Persuasion. You also gain proficiency in Intelligence saving throws. Also starting at 1st level, you add double your proficiency bonus to Wisdom and Charisma saving throws to resist spells and abilities of celestials, fey, and fiends.

Channel Divinity: Suspension of Belief

Starting at 2nd level, you can use your Channel Divinity to reject the existence of a higher being.

As an action, you point to a celestial, fey, or fiend within 60ft and declare it to be a falsehood. The targeted creature must make on a Charisma saving throw, fully resisting Suspension of Belief on a success. Creatures with a CR equal to or above your cleric level automatically succeed on their saving throw, and creatures with a CR of less than half your cleric level (rounded down) have disadvantage on their saving throw.

On a failure, the creature's maximum hit points decrease by half (rounded down) and it becomes incorporeal (if it wasn't already). Being incorporeal, it gains the ability Incorporeal Movement (it can move through other creatures and objects, and it takes 1d10 force damage if it ends its turn in an object), resistance to bludgeoning, piercing, and slashing damage from nonmagical weapons, and any bludgeoning, piercing, or slashing damage it deals is reduced by half (rounded down) for the duration. This lasts for a number of minutes equal to your Wisdom modifier.

If a creature fails its Charisma saving throw while under the effects of a previous use of Suspension of Belief, it is instead completely eradicated.

Practiced Ascetic

Starting at 6th level, you are immune to being charmed by celestials, fey, and fiends, and all allies within 30 feet add your proficiency bonus to saving throws to resist being charmed by celestials, fey, and fiends.

Tools of the enemy

Starting at 8th level, whenever you take radiant, psychic, or necrotic damage, you can use your reaction to gain resistance against that type of damage until the start of your next turn. You can use this feature a number of times equal to your Wisdom modifier. You regain any expended uses when you finish a long rest

Antitheist's field

Starting at 17th level, as an action, you can cast antimagic field by using up an 8th level spell slot or a Channel Divinity (your choice). At the start of each turn, the spell ends unless you use your action to maintain it. For the duration, whenever a celestial, fey, or fiend enters the field or starts its turn there, they must succeed on a Charisma saving throw or be subjected to the effects of Suspension of Disbelief. After you use this ability, you can’t use it again until you finish a long rest.