Endless Blue - Week 22 - Life Began with Water, but Would Not Linger

Evolution

Life Began in Water, but Would Not Linger

The variety of biology in the Endless Blue is astonishing when put into perspective.  With the deeper oceans and wider spaces, life was able to adapt in all directions.  The first unique aspect of Elquan evolution is the development of phytoplankton.  This relatively unremarkable microscopic organism may be the most simple biological life form, but held within it was the potential to populate every ecological niche on the planet.

Sea

Phytoplankton is not a single species, but a multitude of plant types so small it is impossible to see them with the naked eye.  However, their high reproductive rate, in conjunction with their chlorophyllic abilities, means large colonies can be perceived as a fuzzy green haze in the water's currents.  These microphytes -- algea colonies -- still bloom in this same manner today, creating massive swaths of emerald in the azure waters, and serve as the basis of the food chains for every living being in the world.

As plants, they require sunlight to photosynthesize the food they need to survive, so when feeding they tend to be found near the surface of Elqua's oceans.  It is this innocuous behavior that eventually led to the explosion of biodiversity that roams the planet.  The vast, interconnected oceans let the blooming patches excel and spread across the low-albedo waters.  Massive, practically continent-sized algae colonies that dwarf the collected land mass of Elqua many times over could sprout just below the surface of its pristine waters, basking in the life-giving rays of the sun and successfully thrive.

Acting as progenitors, these simple plant-cells multiplied, diversified, become more complex and robust, eventually leading to newer life forms that the phytoplankton then served as a primary food source.  The cycled continued, with those creatures developing more advance bodily systems; organizing cells into organs, creating new senses with which to explore their fertile new world, a bundle of nerves and bones and veins in such infinite diversity that it makes the whole idea of life stemming from a single primitive cell seem ludicrous.  Yet, that is exactly how it happened.

Land

With all this emphasis on aquatic life, one would be led to believe the scattered islands of the world are barren shale and sand.  Nothing could be further from the truth, and life has taken to these new environs just as easily as it did in the seas.  Life, as it is want to do, spreads wherever there is space to exist.  Sometime long in Elqua's prehistory, the predecessor of modern phytoplankton was so plentiful in the oceans that it spread onto dry land, forming a kind of rolling moss, and there began their own digression of evolution.

Elqua became encompassed by an epic ice age, the planet frozen over most of its surface, separating the phytoplankton of the sea from the that on land, and in the ages the frozen environment lasted allowed time for the land locked cousins to evolve further into a divergent life form, a purple-shaded rhodoarchaea that took advantage of the green-hued light that filters through the planet's Sargasso Ring to initiate photosynthesis.  By monopolizing on retinal in the place of chlorophyll, these rhodoarchaea survived in the green hued areas where normal plant life that required red and blue bands of light to survive could not.  With the Sargasso ring circling the globe almost directly over most of the island mega-archipelagos collectively known as the Spine of the World, this ensured a competition-free zone where the rhodoarchaea evolved, and thrived due to the extra concentration of the green light needed for retinal photosynthesis.

These rhodoarchaea reproduced and branched into more complex forms.  However, the cold was not ready to let go if its grip on Elqua.  Slowly the creeping ice sheets that encased the world's oceans began to encroach the lands covered with rhodoarchaea, until its coverage of all the globe was almost complete.  As miles of ice and snow packed over the impotent micro-organisms, the rhodoarchaea fell into a state of stasis, their retinalic  processes slowing down to almost a crawl, preserving the redish-tone plankton until the day would come that the ice shelf retreated and what little land there was could thrive.

Eventually the ice shelf retreated and disappeared, leaving the two ecosystems -- water and land -- truly independent of each other.  Now, where the kelp and seaweed of the waters are a lush green and olive, the plants that thrive in the shade of the Sargasso Ring are purple and violet.  The aberrations the evolved to  live among the magenta leaves are as different from the behemoths swimming amongst the kelp as even the most disturbed mind could imagine.

Sky

But before the total encrustation of Elqua could complete, a second amazing change took place.  An offshoot of the rhodoarchaea began producing methane and hydrogen as a by-product of their retinal-based photosynthesis.  As the life forms multiplied and became more complicated, organelles formed that encapsulated those gasses.  When those organelles became engorged, the lighter than air hydrogen caused these nearly weightless bio-forms to become air-borne, floating a few millimeters above the surface of the land.

The methane was mostly expelled as waste, until a fortunate mutation developed the production of a exothermic acid.  The ejection of the methane, coupled with a squirt of the acid, cause a small combustion and as a result, thrust.  True air-based life was born, the aerostat, and it took the form of organic dirigibles.

As sky life diversified, an organic form of pulse jet arose.  A cone-shaped nose with a sphincter at the tip would open up to allow oxygen into the body.  Inside a heat-resistant organ, the methane is seeped via pores along the chamber's inner surface.  Then two minuscule jets of reactant chemicals derived from the hydrogen created by its retinal process -- hydroquinone and hydrogen peroxide -- combine in the oxygen/methane mix and cause a strong exothermic reaction, giving of enough heat to ignite the rich gases and causing combustion.  Another valve on the other end of the creature serves as the exhaust, directing the exhaust through a final sphincter in the rear of the creature.

The amounts of chemicals produced are incredibly small, and it is only the microscopic mass of the creature and the rapid pace of inhalation and emanation that allows this organic combustion engine to even exist.  The squared-cubed law illustrates the larger the creature, the more massive the amount of chemicals required to sustain flight, and with too large a combustion chamber, the chemical reaction becomes uncontrolled and the temperatures generated would cook the creature from within if it did not simply explode.

From those three microscopic life forms -- the phytoplankton, rhodoarchaea, and aerostat -- diversity bloomed like a cornucopia, spilling into every corner of the ecosystem.  The blood-red riverfalls of the southern ice cap, the gargantuan sea sifters of the periphery, the jet streaming helikites swarming the atmosphere, all can be traced back to tiny, humble, simple celled life.

Endless Blue – Week 21 – The Narrowing Moral Compass

Theology

The Narrowing Moral Compass

Through eyes wide with innocence from their ignorance, primitive pisceans looked at the rolling oceans around them and were bewildered by complexity of it all; how the currents moved, how the waters darkened, how life interacted.  As their minds mulled over these secrets of existence, concepts began to fill in the unfathomable gaps of their knowledge with allegory and myth.  They attributed these ideas to beings greater than themselves, to deities that had originally created them and now guide them through the trails of life in Elqua's seas.

Worshipping gods has been common place in the Known World since before the Kraken Empire, and believed even before the little understood Icht Dominion.  But now, theological belief has been fractured into uncountable sects, factions, and even disparate religions.  However, there is one core belief to all these varied theological systems that is shared in common:  Above the waves is damnation; below the depths is salvation.

That intrinsic idea is borne from both fact and fallacy, repeated over the generations, ingrained into the societies, perhaps has even become a racial memory locked away in the darkest pockets of the piscean mind.  There is evidence for some of it being true -- there are aberrations above the surface that are utterly hostile to anything that breaks the wave into the Vastness, things that will hunt, kill, and consume an unwary mer that swims too close to the open sky.

Conversely, it is believed that the deeper you go, the closer to divinity you attain.  Perhaps this belief stemmed from some ancient piscean's hallucinations while suffering from the Pull, a full sensory experience that was mistaken as the touch of god.  It could be from a more visceral fear, that the aberrations in the Vastness will descend down and tear the flesh of a departed loved-one's mortal coil in a frenzy of ravenous slaking.  Even the most primitive civilizations seem to share in this one common practice, even if its true origin is lost to antiquity.

The Source

The most ancient of the theological systems, and viewed as the most primitive by the self-titled civilized races, is the belief in "the Source".  The Source is the origin, the birth, a non-persona abstraction that created all, even the life-giving waters themselves.  It is symbolized by the egg, an image of fertility and potential, warm and bright, glowing with the energy of life.  The Source is believed to be at the core of the world, pulsating in time with its heart, breathing life into the lifeless waters that drown the land.  It is from Source worship that the tradition of consigning a lifeless body to the deep originates, with the intention of returning a wayward child to its birth womb.

Its practitioners are shamanistic at their core, communing with the Source through nature both animal and plant.  The myriad schools of fish, the expansive reefs of coral, even the very water itself whisper the wonders that are the meaning of life and the piscean place in it.  They communicate with the spirit world, with the Source as its heart, the waves as its breath, and the depths as the embrace of holiness.

Examples: The Narwhal Orcans of the Sahaguin Lagoons cling to most every aspect of their ancient barbarian heritage, even still believing in the Source as the beginning of all life. Signs, omens, and portents are important to them, and those that correspond with an individual's guardian spirit animal having nearly epiphanistic transformative influence.

The Chelon revere a variation of the Source as a non-entity, and instead being the origin of the ley lines that criss-cross the globe at certain intervals, invariably where coral reefs are at their strongest.  It is as much a respect for nature and its complexity as it is with a belief in a higher power.

Pantheonists

Pantheonists believe in a collection of deities that oversee every aspect of life.  They tend to share a common well of cultural belief that forms the interactions of the gods.   Many times disparate but co-existing pantheons share some or all of the same gods, some times with different names, or genders, or importance in the group.

Examples: The primitive races of the Yaun-Teel, Locanth, Kouton, and Sahaguin are classic pantheonists, though each race's take on the Eight can vary greatly.  Most vividly divergent is the Yaun-Teel envisionment, which taints each one of the deities with a primal sin:

Luxuria (extravagance, lust)
Gula (gluttony)
Avaritia (avarice, greed)
Acedia (sloth, despair)
Ira (wrath, vengeance)
Invidia (envy)
Superbia (pride, hubris).
Malvy (deceit, superstition)

The Sahaguin seem to be transforming into a monotheism due to persecution by the Church of Olyhydra, elevating their shark-god Sekolah to "Dominar".  Some of the more isolated settlements of the Mer and Chelon pay the Pantheon respect along with Law Mistress Olyhydra.  The Kouton enfold Source worship into their mythology as their genesis myth while paying service to the Pantheons as the eight "First Ones", who in turn have given birth to countless demigods.  Though they go by many names, the following are the most commonly included deities in Pantheonism on Elqua:

Ahto, Eadro, Icthara, Merrshaulk, Sashelas, Sekolah, Suminarae, and Trishna

Monotheists

Monotheism is a devotion to one supreme deity, and steadfastly holding that any other "god" is false.  These religions tend to be less tolerant of the other theologies, as a primary tenant is absolute omnipotence of their deity.  Basic logic tells you there can only be one ultimate force over all of creation,

The major monotheistic religion -- indeed, the most dominant religion in the Known World -- is the expanding worship of Olyhydra.  She is a stern, harsh mistress, demanding much of Her congregation.  Life is strife, life is toil, and She demands utter and unquestioning obedience in all her directives, the Law.

Examples: Mer are the primary followers of Olyhydra, followed by the disenfranchised Ceph, then a smattering of Chelon and Orcan.  A solid monotheistic movement is burgeoning in the Sahaguin Lagoons with strong undertones of intolerance to Olyhydrans.

Elsewhere Servitude

A dying religion that was at its most powerful during the Kraken Empire.  These ruthless despots worshipped a race of other beings from a realm elsewhere.  Elder gods, more primal than the Source, more alien than the Lumulus, antithetical to the nurturing waters of the Endless Blue.  If not for the seeming withdrawal from our world by these alien beings and the subsequent abandonment of the Kraken, the Occupation of the Known World may never have ended.

Perhaps an even more absolute form of servitude than that of Olyhydran worship, it requires devotion of one's body and soul to the whims of these immoral, immortal entities that do not communicate with our paltry minds, and even if ears could comprehend their dystopian tongues we could never hope to glean the truth behind it.

Examples: Though unproven, the Ceph are frequently accused of serving elder gods, to the point of witch hunts which usually end the traditional method of punishment for heretics: drawn and quartering (or eighthing as is distastefully joked).

Atheists

Only a relatively recent movement away from the millennia of god worshipping, a rising number of individual have been spurning the old ways of servitude and praise toward a non-secular understanding of the world around them.  Branded as the "godless" (always lower-case 'g'; capitalization is a sign of respect and credence) by the devout, these individuals have begun a scientific renaissance like never before seen on Elqua.  Perhaps the most famous of these godless is Seamus Lorwynn, the mer explorer and visionary who is credited with the creation of the new science evolution.  The godless are also proponents of exploring the Vastness, an agenda that puts them at odds with all other theological establishments on Elqua.

Examples: Technically, all Lumulus are atheists, though they do tend to put the scientific method on a pedestal.  Many Mer, spurned by or spurring the Church of Olyhydra, turn to the godless, and those Chelon unable to glimpse the wonders of xanthellae likewise choose this theology, many times out of isolation.

Ancestor Worship

Sometimes viewed as a compromise between theism and atheism, ancestor worshipers do not deify some non-corporeal omnipotence, but instead revere those that came before them, honoring and learning from their earlier lives.  They believe that their forefathers watch over their current trials, and will either send boons for the respectful or banes for the irreverent.  Believers in this form of theology can sometimes form strange  dysfunctional relationships with the departed ancestors, just as them might with living kin.

Examples: Orcans typify the ancestor worshipper, believing that venerating their departed relatives will bring good luck and fortune to them.  Many times they will call out to the dead in the heat of battle to guide their hand, especially when the outcome looks bleak and the relation in question added some vital aspect to the pod's martial style.

"Water is the tears shed by the Source when it realized it was alone.
The flow of the currents are the falling of those tears

as they filled the world with life..."
-- A particularly symbolic passage of Source oral tradition.

Endless Blue – Week 20 – Unguis

Combat

Unguis

Just as life of the Endless Blue has revised and improved on its ways to protect itself with artificial nautiluses and aegises, so to have they refined and enhanced its implements of attack, the ungues.  An ungues is a term referring to any weapon, be it held in the hand, strapped to the body, or slung behind a piscean.  Life is difficult on Elqua, and survival is of upmost importance.  This constant effort of protection through passive and aggressive means has led to the development of some uniquely created items.

On a world where water surrounds you on all side like a cool, glassy cocoon, the materials for construction of tools and items are significantly different.  With sea currents swirling around from all directions, methods such as metal smithing and wood working are impractical.  Constant exposure to water and salt corrodes metals, while porous wood crack and rots.  Just as with nautiluses and aegises, ungues are constructed out of more accessible and practical aquatic materials.  Volcanic glass and sea shell, honed to a razor's sharpness are affixed to bone grips and handles.

Of perhaps even more influence that materials and method in developing unguis is the surroundings themselves.  Water slows movement that in air would be lithe or graceful in the air to a clumsy, molasses-like crawl.  Swinging a weapon is essentially moving a lever -- both ends move for the same amount of time, but the weapon head moves at a higher speed than the haft, thus delivering more power to the impact.  The problem arises with the fact that water doesn't compact well, and that forms resistance to the swing, slowing it down and reducing its effectiveness severely.

Warhammers and flails are unheard of in the military histories of Elqua, being unwieldy and impractical to control in the heat of combat.  Longswords like claymores and katanas are equally ineffective, for they deliver their damage to a victim through a slice.  Instead, weapons that pierce through thrusting thrive in aquatic environments.

Knife -- The most ubiquitous tool on all of Elqua, the knife has a sharpened edge meant for severing things apart.  The shortest of the blades, it delivers the most dexterity but the least damage.

Dagger -- A larger, up to 12 inches, version of the knife, usually with a sharpened edge on both sides of the blade which culminates in a tiny point at the tip, well suited for stabbing.

Punch Dagger/Cestus -- This unguis is designed to fit in a clenched hand, with spikes or knife blades extending forward past the knuckles.  Using the cestus is a simple matter of punching with it, striking with the lacerating capabilities of the protruding points followed up with the force of the blunt impact.

Gaff/Hook -- A truly cruel tool, a sharp, curved hook attached to a perpendicular handle.  Like the cestus, it is held in a clenched hand.  The gaff can be used forcibly, impaling a victim on its hook, or more dangerously, hooking into a gill-slit.  A pair of these can be used in a grapple when the condition of the defeated opponent is not an issue.  They dig into the flesh of an opponent, and the natural fist-position give a circumstance bonus to all grapple checks.

Sickle -- The standard sickle is a farming tool for harvesting crops, and as such it is the most prevalent of any weapon.  It has a curved blade with the sharpened edge on the inside, connected to a short handle.  The blade is designed to hook around a mass of plants, bunching the stalks against the keen edge to facilitate their slicing from the roots.

Sickle (Elquan) -- Another agricultural implement, the Elquan sickle at its core is a bar a little long than the forearm, with a perpendicular handle near one end.  Opposite that is a long, shallow, curved blade that follows the length of the shaft..  Where a sickle cuts on an inward swing, the Elquan sickle cuts on an outward swing.  They make excellent weapons for the common piscean, operating naturally as one would use their arms to block a blow or strike an enemy.  This unquis can be concealed on species such as Locanths and Sahaguin due to the fin-like protrubences along their arms.

Short Sword -- Just as the dagger grew from the knife, the short sword grew from the dagger.  Its blade can be up to double the length of its dagger predecessor, but longer than that and it becomes problematic to stab without the use of both hands, and warrior usually graduate to a spear instead.

Half-Spear -- Essentially just a spear with a shorter shaft, the half-spear is a close combat unquis with no reach.

Staff -- A staff is essentially a spear without the sharpened point.  It is used in a jabbing motion, prodding for the tender spots of an opponent where it can do the most damage.  It is wielded in two hands, but underwater it is a poor double-ended weapon.  As an unquis, it can give the wielder greater range.

Spear --  A long shaft with a point or dagger-like blade on the end, spears are a mainstay in piscean forces.  They length of the weapon gives the bearer reach to attack an enemy before they can close in.  Like the staff, it is used with a thrusting motion.  While a spear can be thrown, it has a range increment of 5 feet and thus very inaccurate.

Polearm -- Polearms developed from simple spears, with their head becoming more complex and specialized.  The first polearms were given a curved hook to the spearhead, and in the hands of a proficient fighter that hook could be caught into the gill-slits of a victim.  From there the variations exploded, and now there are a plethora of designs.  In most civilized militaries, the polearm is the unquis of issue, and entire platoons will be entrusted with polearms of the same design.

Trident -- A trident is a multi-tipped polearm, usually with three tines but can vary in number.  It is synonymous with both martial prowess and with agricultural prowess, and as such is the universal symbol of greatness to Elquan civilizatons.  It is the mantle of power for both terrestrial kings and metaphysical deities, and in heraldry is used to note family nobility.

Ranged Unguis

Unguis that work over distance are rare in the oceans.  Spears are useless when thrown more than five feet away, and a hand-held bow cannot deliver the amount of kinetic energy to fire an arrow in a direct line without it veering off in the currents.  The only true form of ranged weapon that exists is the spear gun, a variation of the heavy crossbow that flings a diminutive javelin about thirty feet via an internal spring mechanism.  Since the Lumulus are the only race with metalworkers in the oceans, spear guns must be imported at great cost.

The net is another common combat tool, but unlike the others above it must have two or more individuals to wield one.  Just like range weapons cannot fire ammunition because of the slowing properties of immersion in water, neither can a net be thrown as it can on the surface.  The users must work in tandem to employ a net successfully, both dragging opposite sides of the net through the water (known as trawling) to capture a creature in the tight woven mesh.  In D20 game terms, the first trawler whose action comes up in initiative must hold his action until it is the other trawler's (or last trawler's, if there are more than a pair) turn to act, then they attack in unison.

Endless Blue – Week 19 – Nautilus and Aegis

Combat

Of Nautiluses and Aegises

Life has devised myriad methods to aid the never ending burden of survival on the world of Endless Blue.  Perhaps the most prolific adaption has been the adaption of thickened skin or chitin into armor.  Right behind that, chasing like a predator keyed in on its prey, is the adaption of lengthened keratin and dentin into weapons.  This tit-for-tat dance of evolutionary one-upmanship is primal in the primitive quest to stay alive, and the intelligent races of Elqua have heightened their competition with the application of  advanced tools and technological innovation.

Taking cues from natural development, pisceans have developed their own protection and armament with the creation of the nautilus, the aegis, and the unguis.

Nautilius

Nautiluses are the armor the races of the Known World have developed to cover the soft, vulnerable parts of their bodies from the teeth, jaws, and claws of very hostile monster that swims the seas.  They cover at least the arms and upper torso of the piscean, with various adaptations to help protect the tail.  Swimming in the piscean form places extreme emphasis on the tail of the body, requiring its flexibility and freedom of movement to accomplish the task evolution honed it for -- mobility.  Thus rigidity would be a hindrance to engaging or escape, and attempts to remedy this paradox have had mixed results.

Using armor breaks up the hydrodynamic curves of a swimmer, causing what is known as drag.  Instead of water flowing easily along the contours of a swimming body, its flow is impeded and jumbled by uneven surfaces.  This interruption of flowing water slows down a swimmer dependent on the type of nautilus worn.

The more esoteric and textured a nautilus, the more drag it incurs.  Further, the bulkier the nautilus, the more restricted the movement and the more difficult it becomes to move the body in the systemically timed manner to achieve sustained swimming.  Light armor slows down a swimmer by 1/4th their swim speed, Medium armor slows down swimmers by 1/3rd their speed, and Heavy armor by one-half.  Spikes can be added to nautiluses to help protect against close-range dangers, but these will increase a nautilus' drag by 5 feet (applied after the halving/thirding/quartering of swim speed).

Aegis

Aegises are a supplemental system of protection equivalent to shields.  They are held by the hand or strapped to the body on the forearm, chest, or back.  They compound a nautilus' amount of drag, and are usually only beneficial on a situational basis.  For example, an aegis strapped on the forearm cannot protect  the body if the arm is being utilized to swim. and an aegis on the back provides no benefit against a spear thrust at the ribcage.

Aegises increase drag, usually reducing swim speed by 5 feet (after nautilus penalty has been applied), and are cumulative.  Using two aegises will reduce swim speed by a total of 10 feet, and only one aegis is ever useful at a time -- there is no significant benefit to covering your body with multiple aegises, as the skill in using them depends on moving the aegis to block.  Further, adding spikes will cumulatively add drag to aegises just as it does for nautiluses, and can effectively make some combinations too bulky to swim in.

Light Nautiluses
Woven Kelp -- This is the most primitive kind of armor, and serves as the base form that all other light nautiluses are derived from.  It is a system of padding woven from harvested kelp.  The padded segments are tailored to the wearer, and a re-laceable system of cording keeps the pads tied together and on the individual.
Woven Cartilage -- Woven cartlidge nautiluses are the same woven kelp pads as the above, but have strips of cartlidge interlaced between the weaves in strategic place to help harden the armor.  The spongy elasticity of cartilage helps absorb impacts from blows that might damage the wearer otherwise.  The primary source of cartilage used in these nautiluses comes from sharks.
Woven Bone -- Exactly like a woven cartilage nautilus, but relies on the more resilient and rigid bone inserts harvested from slaughtered domesticated livestock instead of cartilage from predatory sharks.
Hardened Kelp -- This woven kelp nautilus is treated in an alchemical bath derived from the catalystic properties of acari.  It stiffens the fibrous plant material into hard plates which are then corded together.  The stiffened kelp requires a tight yet flexible weave, making the acari process incompatible with cartilage or bone inserts that depend on the friction of kelp ties to keep the insterts in place.

Medium Nautiluses
Hide -- This is the base form of all medium, and subsequently also heavy, nautiluses.  It employs the same corded interlacing as woven kelp nautiluses, but uses the alchemically tanned skins of animals as the plating.  Bone and cartitlage are both used to support the hide plates, but add nothing exceptional to the overall level of protection the nautilus affords.
Shagreen -- Shagreen is a special kind of hide nautilus made from shark skin.  The tanning process is not a thorough for shagreen nautiluses, resulting in an armor that is not as protective but preserves the natural nap of shark skin, excellent in deterring grappling foes.
Shell -- Shell nautiluses employ patterns of small, overlapping shells to cover the wearer's body.  The shells are pierced a few times along their hinge, then cord is fed through and tied to the hide plating.  The sheer variation of shell shape, color, and size can from mosaics in the nautilus, and a skilled craftsman can increase the nautilus' value many times over though just the sheer artistic expression of these shells.
Nacre Chain -- With an extremely expensive procedure to create,  nacre (or pearl) chain nautiluses are the province of the wealthy and powerful.  Small, interlocking rings are first carved from coral, rock, or other hard material.  These are then inserted into domesticated oysters as an irritant.  Placed under the fleshy body, the animal reacts by secreting an substance called nacre.  This nacre slowly builds up, covering the offending irritant in a layer of beautiful irridescence.  The rings are harvest before too much nacre solidifies and plugs up the ring, and then the rings are assembled into a continual fabric of links.
Xanthellae Coral -- Exclusive to the Chelon, this coral breastplate is literally grown on the body of the wearer.  This nautilus is especially beneficial due to its porous nature, allowing it to completely cover the gill slits along the ribs where other types of nautiluses must leave some space open for circulating water.

Heavy Nautiluses
Echinodermal -- An archaic form of nautilus that fell out of popular use millennia ago, it basically uses live giant echinoderms like starfish as a form of living armor.  In a symbiotic relationship, these over-sized starfish latch onto the flesh of the wearer with their suckers, leaching sustenance from the host in exchange for bodily defense.  The dietary demands of the echinoderms are manageable, and rarely has a host died from the relationship short of extended fasting or wounding on the battlefield.  They were used in mating pairs: one latched onto the host's chest, the other clinging to the back.  Fuller nautiluses used the offspring to cover the limbs and tail of the host.
Shellback -- Used mostly by Sahaguin, Kouton, and the more savage Narwahl Orcans, these nautiluses are literally the exoskeletons of Chelon or Lumulus killed in combat and then scavenged from the corpse.  Its use is utterly reviled among the civilized races, and those that wear it without regard in populated areas may soon find themselves attacked by offended pisceans.  Despite this, there are those so enamored with the deep luster and vibrancy of shellback shells that they will pay a premium for a prize they can only admire in private.
Abalone Plate -- Much like its nacre chain cousin, abalone plate is based on the nacre-like excretions of shellfish.  Whereas nacre chain coats inserted rings, abalone plate is carved from the outer shell of mollusks.  A very specialized craft, portions of shell are chipped and grooved to promote increased creation of abalone.  When sufficient thickness has been achieved, the craftsman severs away portions of the outer shell from the animal without harming it (and hence allowing it to produce more abalone).  These cut-away pieces are then further refined, carved, engraved, and polished into full nautiluses of mythic quality.

Piecemeal Nautiluses -- Not actually a type of nautilus, these methods of armoring are comprised of parts of different kinds of armor, almost as if kit-bashed together from a junkyard.  Only nautiluses of the same class (light, medium, heavy) can be piecemealed because each class is dependant on the previous to work -- medium nautiluses have woven kelp and bone supporting it, and heavy nautiluses have hide linking their parts together.  Average the scores of the two types of nautilus (rounding down) to determine their effectiveness.