Beasts of the depths

The Deep-Sea Witch spoke again in a way someone would call their friend. And her friends started to show up, as, in the waters around her, more and more shadows started to show up. They broke through the surface, revealing their monstrous faces. They looked as if someone dreamed a nightmare about fish and other water creatures in their childhood and tried to sculpt those delirious memories out of tar and bone.
And now, an army of them moved towards the shore. Towards Golvageth

— Chronicler of Golvageth, entry 632

Beasts of the depths are the beings that have been sighted only once in recorded history, an event only a few people know about. The time when Deep-Sea Witch showed up.

Beasts of tar. Beasts of bones - anatomy and morphology

Beasts of the depths greatly vary from each other, both in size and their appearance. The smallest reported individuals were only 30 cm long while the biggest reached up to 5 meters. All of the beasts of the depths are completely Oversaturated with Black Color, leaving their skin harder than steel and continuously secreting a tar-like substance. Due to a thick coating of said substance, their exact shape is hard to discern, although most of them resemble either various reptiles, amphibians, or fish with limbs grafted on them, probably a work of many Adaptation spells.
While both the chitinous "skin" and the substance coating those creatures are black and thick, both of them are at least partially transparent in most individuals, revealing the insides of their bodies. About 80% of individuals have their skeleton visible through their skin. 10% of them also have visible organs. The other 20% are either not transparent or it's impossible to discern any type of tissues inside of them.

Additional Information

Perception and Sensory Capabilities

For the individuals whose guts or skeletons are visible, it is often easy to recognize where their eyes are or should be. The other ones sometimes have at least one bulge visible under the tar dripping from them. It is unknown what type of sensory perception those creatures possess, however, they seem to be able to perceive some area around them and discern living and non-living beings inside of it

Origin

It seems obvious (by their color) that those creatures came from the Black depths of the Southern Sea. However, their exact origins are as of yet unknown. How does something survive the everpresent strength-sapping Blackness?

Entry 634

According to the last report sent by the Chronicler of Golvageth, the Entry 634, it is easy to deduce that beasts of the depths aren't any natural beings that managed to adapt to the Black Color. Instead, they are people who were executed through Sea Grave Banishment, but instead of dying, succumbed to Oversaturation (condition) and turned into monsters.

Death

Once an individual of this species dies, their body starts to melt as if it dissolved itself, leaving only bones and a black spot of Oversaturation (geographic anomaly) behind.