The Entity

Warlock who make a pact with these types of beings have psiconic minded powers that can break the fabric of the universe itself. These warlock make pacts with Elder brains, Beholders, Star spawn, or even entities from the far realm itself. 

Expanded Spell List

The Entity lets you choose from an expanded list of spells when you learn a warlock spell. 

 

Expanded mind

Starting at 1st level, you have an advantage on Intelligence saving throws, you can read, write, and speak deep speech, and when ever some one uses magic to try and read your mind you can try and resist it. Make and intelligence saving throw (you advantage does not apply here ) against their spell save DC (the DM determines if it is not said ) on a failed save they read your mind and they know that you tried to resist on a successful ave they do not read your mind, If the save succeeds   by 5 or more the mind reader takes 1d4 psychic damage.

Dark One’s Own Luck

Starting at 6th level,  you can blast your mind.  as an action you can force a creature within 120 feet of you to make an Intelligence saving throw. On a failed save they take 3d8 physic damage and they are stunned for 1 minute, on a successful save they take half as much damage and aren't stunned. The stunned creature may make an Intelligence saving throw at the end of of each of it's turns ending the effect on a success. 

Fiendish Resilience

Starting at 10th level, you gain resistance to psychic damage 

 

Mind Shape

Starting at 14th level, you can use a reaction to force a creature casting a spell or making an attack  to make an Intelligence saving throw against your spell save DC. on a failed save they take 8d10 psychic damage and you choose the target or area of the spell or attack. on a successful save they only take the damage.