Homebrew Flayer Species Details

Monstrous Flesh

Flayers are demi-aquatic monsters, with octopian flesh, tough coral-like plates of natural armor, and great strength and constitution. With claws, infected jaws, and countless flailing tendrils, they have an arsenal of innate methods to fight with their rightfully earned title of Flayer, although Aware Flayers tend to be less extravagant in their body's abilities in exchange for their mind. With most, if not all layers of society being rightfully afraid of the monsters of the world, Flayers easily fall into a fearful category, something to be avoided or attacked on sight.

Product of Plague

Being products of a disease (which can be found in the Dungeon Master's Guide, Sewer Plague but with save DC's of 18. A creature with 0 levels of exhaustion has advantage on their saving throws against the disease), a Flayer comes into being from mutation of a corpse infected with the Flayer's strain.

Whenever a creature is bitten by a Flayer, they may be infected with a highly dangerous strain of Sewer Plague, and slowly succumb to the disease in many cases. Due to the incredibly violent, mutating, and magically resilient nature of the disease, it is incurable without a spell of 7th level or higher. Otherwise, the only option is to naturally resist it, in which reducing the induced exhaustion is one of the only methods possible to assist the inflicted.

Aware, a Monstrosity

A Flayer may or may not remember their past life, and similarly may or may not be influenced by their previous self. Some cases are haunted by brief glimpses of memory, some are harrowed with horrific deeds, and some may even seek to take revenge on those who wronged them in their past life.

Flayers have no society, and little interacting life. They find begrudging peace among other monstrous creatures, whether or not they are mindless or aware. Due to being a literal monster, an infectious one too, fear is abundant. To be a Flayer and to be aware, is to be ailed. Nothing can cure it outside of legendary power, and to die is all but permanent with nothing that would resurrect a Flayer. After all, what legendary powers would lend themselves to a Monster? What servitor of Faith would bring the gift of another chance at life to just another Monster?

Mindless or Aware

Flayers tend to fall into two categories, the monster so highly mutable that no specific subraces or variations can be broadly specified.

Most Flayers, having been all of them until recent history, were mindless monsters. Demi-Aquatic, feasting on fish, spreading infection, and leaving prey with countless lacerations for them to slowly perish from. Feeling no remorse, no emotion of the self, they were lesser than wolves, but intelligent enough to problem solve.
Recently however, Flayers have begun coming into being... Aware. Remembering fragments of their past life, an amnesiac in the body of a monster, their body irreparably mutated, impossible to be who they once were without all but the most legendary of spells, the highest of miracles, a true resurrection in mind and body. An Aware Flayer is a much less daunting foe than their monstrous counterparts, but they can think. With any variety of ability such as a sense of inner peace and discipline, a remnant of a magical bloodline, a fierce rage, or an otherworldly connection that refuses to let go, a Flayer can be who they once were, again in their new life.

Flayer Traits

You, you're different. As an aware Flayer, you gain the following traits.

Ability Score Increase

As a Flayer, you naturally possess greater strength and constitution. Your Strength and Constitution scores both increase by 2.

Age

Flayers have no defined lifespan, mostly due to lack of research, being slain, and their highly mutative biology.

Alignment

Flayers tend to be neutral.

Some become territorial and lawful, some turn unpredictable and chaotic.
Some are aware and good, some are aware and evil or mindless and hostile.
In a vast majority, Flayers have a neutral aspect.

Size

Your size is Medium. To set your height and weight, choose a size modifier between and including 8 and 26, or to do it randomly, start with rolling a size modifier:

Size modifier = 2d10+6

Height = 5 feet + 10 inches + your size modifier in inches

Weight in pounds = (your strength score + your size modifier) x 20 | If your weight is below 500, add your strength score x 20 again. Repeat if necessary.

Speed

Flayers are bulky, and heavily weighted down from the fluid weight squelching between the plates of natural armor and their octopian flesh.
You have a base walking speed of 25 feet.

Languages

You can speak, read, and write Common and Primordial.

Regeneration

As a different mutation of Flayer, your highly mutated body possesses extreme regeneration in bursts, momentarily surpassing that of even the iconic regenerating monsters being Trolls.

At the start of each of your turns, if you have at least 1 hit point, you can choose to regenerate. If you choose to do so, you spend one of your hit die. Roll it, add your Constitution modifier and your Proficiency bonus, and regain hit points equal to the total.

Additionally, whenever you take a short rest and spend hit dice to regain hit points, you add your proficiency bonus to the hit points you regain for each hit dice you spend, and you can reroll the result whenever the die rolls a number below half the amount of sides it has. You do not have to use the new roll, and can continue rerolling.

Natural Armor

You have tough, coral-like armor. When you aren’t wearing armor, your AC is 13 + your Constitution modifier. You can use your natural armor to determine your AC if the armor you wear would leave you with a lower AC. A shield’s benefits apply as normal while you use your natural armor.

Tendril Hand

As a Flayer, one of your arms turns into a mass of octopian Tendrils where the hand would be, which can reach out to things up to 10 feet away. Your Tendrils can still function as a hand to grab an object such as a weapon, but you lack the ability to grab much more than what a regular hand normally could. You can change which hand is a mass of tendrils as an action, your other hand bloating into a mass of tendrils as the prior mass of tendrils recedes and becomes a hand, but one hand must be tendrils and one hand must be a hand.

Additionally, they can be used as a natural weapon. On a hit, the Tendrils deal Slashing damage equal to 1d4 + your Strength modifier, and the target must make a Strength saving throw. If the target is one size larger than you it gains advantage on the saving throw, and if it is two or more sizes larger than you it automatically succeeds.
The DC equals 8 + your Proficiency bonus + your Strength modifier.
On a failed save, you can move the target up to 5 feet in any direction to an unoccupied space.

The damage of this natural weapon increases to 2d4 when you reach 5th level, as your mutative nature increases the amount of tendrils, which additionally increases your manipulative reach (not for attacks) to 15 feet.