Homebrew Dark Aberration Species Details

 Description: Dark Aberrations are bipedal, dark shadowy beings. People have mistaken them for shadows, but they are quite material in comparison. Their bodies lack a definitive neck, with their torso simply narrowing out to a small, round head. The face is very simple, with swirling white voids for eyes, and segmented sections of white as its mouth. It is a pitch black creature, and those who touch it recall the texture of stretched satin or velvet, being very smooth. They walk with hunched backs and drag their long, three-fingered arms on the floor. Wisps of dark energy, as well as what looks like strips of dark cloth, emit from their bodies like a shrouding raiment. They are capable of speech and expressions, having very deep, throaty voices.

 Social Structure: Dark aberrations live in groups called shades, where they roil about one another, making thee illusion of one dark mass. Alone, they are weak, but together, they pose danger to even skilled adventuring groups. There is no clear leader in a group, but it is assumed that the most powerful individuals directed the weaker ones They are curiously intelligent and are capable of symbolism. They do not grasp the concept of sex and gender inherently. 

 Behavior: They rove about the depths of the Underdark, mainly avoiding the illithids and other more powerful denizens of the darkness. Unlike other creatures of darkness like shadows or shadow fiends, dark aberrations are only slightly affected by dim sunlight, as they are not full shadow creatures.Occasionally in dusk, dawn or nighttime conditions lone (or small groups of) Dark Aberrations seem to enjoy terrorizing surface dwellers by slinking around and causing havoc and discord. Usually this is not done to cause direct harm, but more as horrifying pranks and scaring weaker or lone creatures. Groups of Dark Aberrants, however, have been known to raid surface settlements from late day till dawn.

 Names: Dark aberrations take names which sound very ominous. Some examples are Orregauth Il'Nath, Morduk el'Shabbarath, Polmug Gre'Naut, Shezalarch, Uthgar

 Age: Dark aberrations do not age or grow and they look the same from the day they are made to the day they die. Dark Aberrations reach adulthood at around 150 years and can live up to 500 years old (Random starting age is 125 + 5d20 years).
 Alignment: Dark aberrations can be any alignment, although most tend to be evil in nature and generally love to sow terror and chaos seemingly for fun.
 Height and Weight: Dark Aberrations are generally between 4' 7"  and 7' tall (52" + 3d12 height modifier) and weigh 130 and 220 lbs. (100 + Height modifier x10).

 Disclaimer: This was made at the request of one of my players and is based on the DanDWiki version (Dark_Aberration_(5e_Race)). All credit, where applicable, goes to the originator of the Wiki article. I have adjusted the race (to make it less OP) and entered it into D&D Beyond for personal use and claim no rights to it or any images I have used.

Dark Aberration Traits

Tall bipedal creatures appearing like darkness materialized

Languages

 You can speak, read and write Common and Abyssal.

Ability Score Increase

 Your Dexterity score increases by 2, and your Charisma score increases by 1.

Darkvision

You can see in dim light within 60 feet of you as if it were bright light, and in darkness as if it were dim light. You can't discern color in darkness, only shades of gray.

Amorphous

You are extremely flexible and limber. You can move through a space as narrow as 1 foot without squeezing, any items that cannot fit through a space you pass through must be taken off/left behind. You have advantage on checks made to escape being grappled and typically applied restraints can't hold you. In addition, you can don or doff armor in one round.

Shadow Step

 On your turn, if you haven't moved and you are in darkness, you can use your bonus action to teleport 20 feet to an unoccupied space you can see. If you do so, you can't benefit from any bonus to your speed until the end of your turn. This replaces your normal movement in that turn.

Dark Infusion

 You draw strength from the dark. When in darkness, (at third level and above) you may expend a bonus action to draw in the essence of it. You regain hit points equal to 1d8 + your Charisma modifier. You can't gain hit points over your maximum with this trait. You must finish a short or long rest before using this trait again.

Bright Sunlight Sensitivity

While in direct sunlight, you have disadvantage on Attack rolls, as well as on Wisdom (Perception) checks that rely on sight. You are not very susceptible to  indirect sunlight and thus operate normally in dusk or dawn, or even overcast conditions. Sight checks made into an area of bright sunlight still incur disadvantage.

Radiant Damage Vulnerability

Although you are not as susceptible to light conditions as some other Underdark denizens, your inherent mysterious association with the dark and undead you them susceptible to Radiant Damage, giving you Vulnerability to attacks of this type.