Your Intelligence score increases by 2, and either your Wisdom or Charisma score increases by 1.

Illithids fully complete ceremorphosis by the age of 9, and have become fully mature and complete in their education by age 15. Illithids live longer than humans, but they do eventually die at around the 120-year mark.

 Illithids normally have a natural tendency towards hierarchy, discipline, and cruelty, and have an alignment of lawful evil. Some individuals find themselves developing more-individualistic personalities than their fellows early after ceremorphosis and have an alignment of neutral evil. A minority lack the characteristic sadism of their brethren while retaining their preoccupation with the organization, and have an alignment of lawful neutral. Any illithid of any other alignment, usually the product of unusual circumstances such as mutation, magical alteration, extensive contact with unshackled non-illithid minds while cut off from the networked communal intelligence of their colonies, or intervention by otherworldly forces, is likely regarded by others of its kind as either a disgusting social deviant and pariah, or, at worst, as pollution to be purged. Many such illithid are either mentally wiped blank and re-educated or simply thrown out of their home communities if their natures are too open and offensive to their fellows' sensibilities.

Most illithids are at least as tall as tall humans, standing at least a few inches shy of six feet, but their bodies very slender and emaciated, weighing much less than an average being of their stature. Your size is Medium.

Your base walking speed is 30 feet.

Your creature type is both humanoid and aberration. Even those illithids who have undergone alignment shifts via magical means or mutations struggle to understand the feelings of less-alien beings. You have disadvantage on all Charisma ability checks in which you are not proficient in.

Your darkvision has a radius of 120 feet.

When you reduce a living creature within 5 feet of you to 0 hit points, you can, as a reaction, devour their brain completely gaining temporary hit points equal to your level + your proficiency bonus. In addition, you may receive the answer to one question that the consumed brain knew the answer to. This creature must have a size of Medium or smaller. Alternatively, you may consume the brain of a creature that has died within the last minute and gain the same benefits. You regain use of this trait once you complete a long rest.

You can use your action to emit a psionic blast in a 15-foot radius around you dealing 2d6 psychic damage. When you use your mind blast, each creature in the area of the blast must make a Intelligence saving throw. The DC for this saving throw equals 8 + your Intelligence modifier + your proficiency bonus. A creature takes 2d6 damage on a failed save, and half as much damage on a successful one. The damage increases to 3d6 at 6th level, 4d6 at 11th level, and 5d6 at 16th level. After you use your mind blast, you can’t use it again until you complete a short or long rest.

You can communicate mentally with another creature that knows at least one language within a 60-foot radius. This creature doesn't need to share a language with you but unless they have telepathy themselves they can only receive and respond but can't initiate or terminate a telepathic conversation. You must be conscious to use this trait and cannot telepathically communicate with multiple creatures at once.

You can speak, read, and write Undercommon, and Deep Speech. Undercommon is a language of commerce among the subterranean races in the same way Common is among the surface dwellers.