Essog

The Essog, also known as the Kin'Zok and the Libraries to citizens of the Southern Sea and humans, respectively, are sentient aerobic methanophile zooid colonies native to the Massog system. They arrange themselves into several Great Libraries, enormous landscapes of neurological tissue that line the ocean floors of Massog. These Great Libraries lead smaller copies of themselves known as Libraries, which in turn lead mobile colonies known as Drones. A joint project between the Great Libraries leads interstellar expeditions, officially making the Essog a member of the galactic community.

Biology
The microscopic form of an Essog is essentially a free-floating neuron. The three flagellum on the surface of the cells are mainly used for locomotion, but the shorter two can be used to link with a receptacle on another Essog cell, which in large groups can be used to create a sentient brain. Essog cells initially evolved these connectors to prevent filter feeders from consuming them in their microscopic form, with the neurological connection coming later. The Essog are eukaryotic by human classification, having absorbed methanophile bacteria early in their evolutionary history into their cells.

The most common form that the Essog take is a "library". Found underwater, these are large coatings of Essog cells attached to each other, as well as free-floating organisms exuded by the structure. To a human eye, these would resemble slightly greener areas of water, with a thick moss growing on the ocean floor. These "libraries" can range from the size of a bowl of water to the size of an ocean, though vast Essog such as those would only be found on Massog.

When an Essog library wishes to create a drone, it will deposit a large cluster of cells into the water around it, which will become the Essog's "brain". The microscopic Essog in the water will rush to the structure and form the body of the new drone. Depending on what has already been built, they will specialize. For example, if the microscopic Essog detect that the cells near them have formed nerves, they will specialize into muscle cells and create a limb around the nerves. New cells will be able to tell that a large muscle has formed, specialize into skin cells, and grow a skin over the muscle. Theoretically, an Essog drone is immortal, as its cells can revert back to unspecialized cells and become a newborn drone once again, but most are disseminated back into the library that they came from before any chance of dying of old age occurs. Through machinery and genetic engineering, better and more efficient ways of producing drones have been developed by the Essog, but they are often still produced the "old-fashioned way".

When an Essog colony needs hands, it will create a colonial animal for work. These drones are pentaradial, resembling a series of starfish with elongated limbs attached to each other in a form resembling an eel. Each segment of a drone's body has five limbs, which are used for both movement and manipulation of objects. An Essog drone is semitransparent, and its internal organs can be seen from the outside of its body, as well as its single, compound eye, which is behind its mouth and within its head. Most Essog possesses neither a tongue nor teeth, and their mouths arecircular, with no jaw.

The surface of an Essog drone is coated in a sort of protective mucus, which hardens over time to produce an armour-like coating along the Essog's body. While easily penetrated by even the dullest weapon, it provides a slight protection against small predators and underwater parasites. Essog have the natural ability to absorb metal into themselves and remove their impurities. This was originally adapted as a form of defense, as the metal would form plates and spikes along their back as well as "beaks" that would allow the Essog to better hunt prey and fight predators. However, this ability has been lost to all but the Southern Seas libraries, though the vestigial metal-purifying ability remains in the other Essog cultures.

Essog are aerobic methanophiles, and need to consume both methane and oxygen to survive. The oceans of Massog have both methanotrophic and photosynthetic organisms, so the Essog can filter both from the water. However, they cannot filter either from the air, so they are entirely aquatic organisms.

An Essog library is a memory and knowledge storage area, as well as the closest mentally to other galactic species of the Essog forms. On Massog, several large libraries exist that are analogous to nation-states, who have the loyalty of smaller libraries on other parts of Nassog, and, more recently, on other planets. Essog drones as well as these smaller libraries have no fear of death and will disseminate themselves back into the library that produced them so that it can absorb their mass and their knowledge. An Essog drone is essentially a copy of the personality and memories of the library that produced it unless in its isolation it is changed by its experiences and becomes different.

Prehistory
Essog prehistory is very poorly understood compared to the prehistory of other species, due to the fact that the Essog do not possess any bones. However, from the few drones that possessed metallic exoskeletons and teeth, some knowledge has been discovered.