For context on my Illithid characters and their Caste system (and a copy-paste from my headcanons section of my discord), you will occasionally notice that some of my characters have the word Minor associated with them, this does not at all have anything to do with a character's age and is entirely from a taxonomical standpoint. If for whatever reason I am talking about an underage Illithid I will address them as either a Newborn, Young Illithid, or Youth. Specifically, my Illithid come of age at 20 and while I do have characters below that age, there will be no NSFW drawn of them period, I might not even post them here unless they show up with one of the older OCs as a side character.

Illithid Caste System

The Primordial Illithid society resembled that of an ant colony but on a smaller scale, their species naturally came in three basic castes that had their own biological functions. The modern Terrestrial illithids have retained the physical characteristics of their ancestors, though are now much smaller, and they no longer serve any function in their society.

The three base castes are:

- Major
- Height Range: 6'8 - 7'5
- Prey species: Humans, Half Orcs, Dragonborn, High Elves, Tiefling
- Physical Traits: Longer tentacles, Longer and usually pointed braincase
- Birthrate: 1

- Media
- Height Range: 5'7 - 6'9
- Prey species: Humans, Elves, Tiefling, Drow
- Physical Traits: Medium tentacles, Rounded head, Most often have "beaks" - but not always, this trait is seen less with each generation.
- Birthrate: 3

- Minor
- Hight Range: 4'5 - 5'9
- Prey Species: Gnomes, Halflings, dwarves, Drow
- Physical Traits: Shorter tentacles, Longer and pointed braincase.
- Birthrate: 4

Minors have a few unique features and are the most faithful to their home world ancestors, the first being two long and thin feeding tentacles that remain retracted in their throats until they find prey, and two specially adapted tentacles on their forehead used as communication displays, these two traits have been entirely lost on the other two castes, Despite these 4 extra "tentacles" they are not to be mistaken for Ulitharids. Minors are also extremely rare outside of colonies despite being the most plentiful caste, this is due to their function in their original society as caretakers and homemakers, a Minor is more likely to take re-education over expulsion due to their social needs and most renegade Minors tend to be Inter-caste.

Each caste is biologically inclined to its individual food items, even with free access to enthralled meals of any race, they will usually stick to their preferred prey.

Two additional castes:

- Ulitharid
- Height Range: A foot above the intended caste's average height
- Prey Species: Humans, Elves, Tiefling, Dragonborn, Half Orcs
- Physical traits: Two additional tentacles, usually thinner but longer than the main four.
- Birthrate: 0.002
- Any caste can become an Ulitharid.

Inter-caste
Inter-caste is the closest thing you will get to a hybrid when it comes to Illithid. Each tadpole holds the full range of natural genetic code and has the potential to become any caste, what determines the end result is the tadpole's lineage; If the parent was a Media, the child will also be a Media. In the case of Inter-caste, however, one or two traits from one of the other castes may unintentionally come through. This can result in a Major with shorter tentacles or an unusually tall Minor.

Neither of these castes are natural, Ulitharids specifically did not exist until Elderbrains took over the race and while inter-castes did happen on occasion, they were much rarer before the Illithids were domesticated.

Other traits unrelating to castes:

Illithid DNA is very malleable and significant changes can be made in a single generation, while Elderbrain aren't the best at gene editing some differences can clearly be seen between colonies. The most noticeable example is their foot configuration: while Illithid living in a more aquatic environment will have the standard two webbed toes tipped with a large claw, their somewhat "dryer" cousins may sport a more humanoid approach with 3-4 webbed toes in the traditional Illithid style. A mindflayer with Human hands or feet however would be seen as deformed.

Tentacle arrangement, much like castes, is lineage-based, an established colony will usually have a healthy mix.