Whispering Aura. At the start of each of the warlock's turns, each creature of its choice within 5 feet of it must succeed on a DC 15 Wisdom saving throw or take 10 (3d6) psychic damage, provided that the warlock isn't incapacitated.
Innate Spellcasting. The warlock's innate spellcasting ability is Charisma. It can innately cast the following spells (spell save DC 15), requiring no material components:
At will: detect magic, jump, levitate, mage armor (self only), speak with dead
1/day each: arcane gate, true seeing
Spellcasting. The warlock is a 14th-level spellcaster. Its spellcasting ability is Charisma (spell save DC 15, +7 to hit with spell attacks). It regains its expended spell slots when it finishes a short or long rest. It knows the following warlock spells:
Cantrips (at will): chill touch, eldritch blast, guidance, mage hand, minor illusion, prestidigitation, shocking grasp
1st–5th level (3 slots): armor of Agathys, arms of Hadar, crown of madness, clairvoyance, contact other plane, detect thoughts, dimension door, dissonant whispers, dominate beast, telekinesis, vampiric touch
Dagger. Melee or Ranged Weapon Attack: +5 to hit, reach 5 ft. or range 20/60 ft., one target. Hit:4 (1d4 + 2) piercing damage.
Warlocks of the Great Old One gain their powers through magical pacts forged with eldritch entities from strange and distant realms of existence. Some of these warlocks associate with cultists devoted to these entities, as well as aberrations that share their goals, yet other warlocks of the Great Old One are experts at rooting out the insanity and wickedness inspired by bizarre beings from beyond the stars.