Omnipotence Blast

Through intensive study and guidance from your deity (or deities), you have gained knowledge of a technique that uses your life force as a conduit for celestial energy, enabling the vessel to charge and release that energy as a destructive beam.

Requirements to use: Must be at full health or above, have all channel divinity’s available to use, or in the Warlock's case their highest level spellslot, and a tempered piece of the Astral Plane equipped or an enchanted prism. 

Range: Sight/2 miles to the horizon
Takes one minute to charge and requires concentration.

Take damage equal to half your hit point total, rounded down. You send out a ray in a direction you choose 30 ft. in radius with a range equal to where you can see. Each creature caught in the blast must roll a DEX save equal to your Spell Save DC plus either your INT, WIS, or CHA modifiers. On a success, they take half damage. On a failure, full damage.
Depending on how many deities you call upon, and how many answer (DM's discretion on conditions for deities to come to your aid), deal Xd20 force damage, where X is equal to your combined class levels based on the prerequisites (base type; can add more types based on type of deity answering your call) plus 2d20 damage per “deity” that channels energy into the blast.
Upon firing the blast, take a level of exhaustion.