Castlecraw

At the height of the Blue Bile epidemic, countless creatures perished. Man and elf-kind struggled to find a solution to this pressing illness as nothing appeared to slow its effects. That was until a curious creature -the benign Castlecraw- was found in abundance on the Lattish dockyards. Though a nuisance, it became increasingly apparent that they were totally immune to the pathogen. By collecting their blood, the scholars were able to create a cure to the plague. Today, they’re seen with mixed eyes. Their blood was a saving grace but they aren’t exactly helpful. In any case, their contribution to medicine has dwarfed many of the critics of this remarkable creature.

#### Physiology and Anatomy

Castlecraw are a species of crayfish. They’re best suited for murky, polluted waters. They’re able to filter oxygen from water even when it is particularly contaminated by other agents- even the toxins generated by waste. They have some of the strongest immune systems exhibited by any organism, allowing them to reliably fend off pathogens in otherwise disease-ridden areas. They filter the excess waste they collect through their gills into a specialized organ attached to the mouthparts. This waste is a combination of pollutants and earth debris. When it is exposed to the Castlecraw’s saliva, this substance becomes vicious like mud. It can then be shaped like clay and hardens within a few minutes. This substance is fairly sturdy once it has thickened, able to withstand strikes like a rock of proportionate size.

Unlike their cousins, they’re better equipped for a semi-terrestrial lifestyle. Their gills are internally contained within a bubble under their armored plates to keep them moist even while out of water. This allows them to breathe on land far longer than any of their cousins. Their limbs, claws, and tail have grown larger to serve as tools to move in and out of their shallow habitat. They’re more mobile than other crustaceans. Their claws additionally have a curved notch to assist in molding of mud, allowing them to manipulate the mud they produce with surprising intricacy and intent. Similarly, the scutes forming their tail fin have an extra set of articulable points at their base so that they may be angled to curl around each other. Castlecraws often use this to form a basket; loading balls of hardened mud and stones into it before hurling it at the desired target. Being so muscular, these impacts can strike with the forces able to crack mud defenses and even wood.

Omnivorous, Castlecraw are well-equipped to make do with anything they come across. They have eyes on ends of stalks which can move around independently of each other to focus on different points of interest. A Castlecraw’s mouthparts are general and designed to appropriately consume biomaterial of any sort as efficiently as possible. They can stomach detritus, carrion, and fine particulates that would otherwise be unpalatable by other organisms. Though they’re rarely the ones doing the hunting. More often than not the Castlecraw takes on the role of scavenger of the shoreline, content to feed on whatever is tossed overboard in a shipyard or washes ashore on a beach.

#### Psychology

Castlecraw are both intelligent and social invertebrates. They form groups or ‘creeds’ of up to ten adult individuals. Creeds will work to construct monolithic nests from their mud as a place to both rear young and hide from potential predators. Creeds of Castlecraw may also establish borders and satellite nests to protect particular patches on the shore. They aren’t aggressive toward anything larger than a Nera’nak -choosing to flee aggressed- but are considerably territorial against other creeds or rogue Castlecraw. Battles between Creeds may last for generations with each side sieging the other, blowing holes into their nests using hurled debris from their tails. Castlecraws rarely take prisoners.

They have little regard for the happenings of other creatures provided they’re left alone. They cannot be tamed or domesticated, but are occasionally harvested despite their outwardly armored demeanor. Should one be able to get their armor off- they make for a common monic delicacy.