Prerequisite: Death, War, Conquest, or Pestilence Patron
When you cast eldritch blast, instead of making attack rolls, you can force all creatures within a cone originating from you to make a Dexterity saving throw against your spell save DC, taking the damage of all beams of your eldritch blast on a failed save, and half on a successful save.
The size of the cone is a number of feet equal to five times your warlock level. You can do this a number of times equal to your proficiency bonus per long rest.