Homebrew Broken Illithid - Mindflayer Species Details

In terms of height, weight, and build, mind flayers were roughly comparable to thin humans, but it was at this point that any external comparison to humanoids ended.A mind flayer's body was, in fact, a gruesome mockery of the humanoid form. An illithid's flesh, was soft, supple, moist, and rubbery, resulting in an unmistakable texture easily distinguishable from any other creature by anyone familiar with it. Their skin ranged from mauve to greenish-violet in color. Mind flayers that were healthy from brain-rich diets excreted a thin film of slimy, glistening mucus that kept in moisture and gave off a faint odor similar to onions, garlic, or even vanilla, although the smell was imperceptible from afar. Their blood had a silvery-white color.

An illithid's bulging, ridged, elongated headwas reminiscent of an octopus, with a cluster of four flexible, unsegmented, extendable, purplish-black tentacles surrounding their mouths. The tentacles could range in length from 2​ to ​4 feet (0.61​ to ​1.2 meters), appearing shorter when an illithid was at rest. They writhed and undulated almost constantly and absent-mindedly while the illithid pondered or otherwise was not using them,and flexed in anticipation when sentient beings drew close.They were also incredibly dexterous, powerful, and could be fully controlled by the mind flayer to perform both fine and strength-based tasks.

In many apocryphal descriptions and diagrams, mind flayers were portrayed as having beaked mouths, possibly owing to their octopus-like heads. In reality, an illithid's mouth was more like that of a lamprey, with a circular, jawless orifice ringed by several rows of small, rasping teeth.The tentacles hung above and around their mouthsand an oily slime constantly dripped out of their maws.Illithids did not possess exterior ears, rather hosting small, fleshy, ridged holes on both sides of their heads,nor did they have nostrils.Their eyes, sheltered by brow ridges, were uniformly pale and devoid of pupils in  addition to being bloated and featureless, similar to those of blind cave fish.

Illithid hands were long, slender, and lacked an index finger, but were otherwise similar to those of normal humanoid creatures. The remaining fingers and opposable thumb were red to mauve in coloration, and their nails were thick and black. Though illithid nails seemed dangerous, they were actually blunt and composed of soft cartilage, and so had little hope of being effective weapons. Illithid feet were webbed and had only two toes, which were also nailed and could flex widely apart, as if to assist in swimming.

Illithids were known to dress in flowing and dramatic robes and cloaks.They were rarely seen without distinctively two-lobed boots, which concealed their webbed nature.They often wore high, flaring collars, dark hats, and various other pieces of ornamentation.

CC the forgotten realms wiki for base level wording for the Illithid descriptions

Personality:

Now that you are free, you recall you're most of your former life. Your memories from your time in under the Elder Brains control are blurred and hard to recall. You remember a lot of the information you've learned, but not necessarily how or when you you learned it. 

This leads to a lot of variance in priorities and typically results in feeling ostracized from everyone you've known.

Broken Illithid - Mindflayer Traits

Since you freed yourself prematurely, you have lost most of your psionic abilities and have extra susceptibility to being charmed

Lost Connection

Due to the absence of an Elder brain or dominant figure in your brain you have a harder time resisting the will of mind controlling abilities. You have disadvantage on saving throws against magical charm effects.

Natural Beak

Your transformation into the Mindflayer body left you with a natural beak, strong enough to cracker skulls to devour brains.

Illithid Hunger

The innate hunger gives you a natural instinct to devour brains when the opportunity presents itself. While you have a humanoid grappled or score the final blow on a humanoid during your turn you may make an additional bite attack with your beak as a bonus action for increased damage and healing half on the damage done. 

Psionic Connections

Your severed connection to the Illithid Psionic network leaves you with the ability to send your thoughts to a creature within 120ft that you can see

These thoughts can be either words or emotions, please speak with your DM for further ruling. 

Stats!

The default for Broken Illithid's would be +2 to Intelligence and +1 to Dexterity.

With my love for Tasha's, I am setting the default as personal choice. 

Darkvision

Due to their time in space and underground Mindflayers have developed darkvision

Mind Blast

 The mind flayer magically emits psychic energy in a 30-foot cone. Each creature in that area must succeed on a DC 15 Intelligence saving throw or take 2d8 psychic damage and be stunned for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

Language

Undercommon