Great Old One Patron Warlock Guide

You can communicate telepathically with any creature you can see within 30 feet. You don't need to share a language for the creature to understand your telepathic messages, but the creature must be able to understand at least one language.

You gain additional spells that count as warlock spells for you: Dissonant Whispers, Tasha's Hideous Laughter (level 1); Detect Thoughts, Phantasmal Force (level 3); Clairvoyance, Hunger of Hadar (level 5); Dominate Beast, Evard's Black Tentacles (level 7); Dominate Person, Telekinesis (level 9).

You learn additional psionic spells that count as warlock spells for you. These spells allow you to invade and manipulate the minds of your enemies.

When you deal damage to a creature, you gain advantage on attack rolls against that creature until the end of your current turn, as you peer briefly into its immediate future. Additionally, that creature can't make opportunity attacks against you for the rest of that turn.

When you place a curse on a creature (such as with the Hex spell or a warlock feature that curses), you can use a bonus action to give that creature disadvantage on saving throws against one ability of your choice until the curse ends.

Your thoughts can't be read by telepathy or other means unless you allow it. You also have resistance to psychic damage, and whenever a creature deals psychic damage to you, that creature takes the same amount of psychic damage.

You can use your action to touch an incapacitated humanoid. That creature is then charmed by you until a Remove Curse spell is cast on it, the charmed condition is removed from it, or you use this feature again. You can communicate telepathically with the charmed creature as long as the two of you are on the same plane of existence.