A I: Cardians

Written by Neons-Mindrealm

Cardians
Parasitic Abominations of Alterna I: The Lands of Paradise

Origins:

As one of the many parasites created by Fuahng, Cardians are said to originate from the arcanic energies absrobed by the hard fleshed bark of the Living Decay's Hollow Tree. Where they hatch from as hundreds of larvae to then infest the muddy waters of the swamp, waiting for a suitable host to feed on.

Current Habitat:

Cardians greatly depend on a moist and mostly dark environment. Which is why they can mainly be found swimming around in the lakes and creeks of the Living Decay when they are stll just a larva, searching for a suitable host to infest.
Once they have managed to successfully find and pierce the skin of another living being, the Cardian larva would then slither its way through the arteries of its host, before nesting itself in one of its host's heart ventricles, and start its incubation phase.
If the incubation phase of a Cardian ends anywhere except for the Living Decay or a damp cave, however, the fully grown Cardian would most likely not survive for very long, and simply just dry out and die within 1 to 2 days.

Average Size / Height:

As a larva, Cardians often just reach a length of around 3 to 5 millimeters, with a width as thin as 1 or half a millimeter.
Once their incubation inside of a living host is complete, though, their full size would range from a few centimeters up to multiple meters, mainly depending on how big the heart of its host is.

Diet:

As a unique type of sanguivore, Cardians feed exclusively on the oxygen rich blood of still living beings, either by absorbing it directly through their skin from within their host's body if they are still just a larva. Or by extracting it from the veins of another creature, after forcefully penetrating their skin and anchoring their fully grown tendrils within the creature's major arteries.

Physical Appearance:

The main body of a Cardian consists of multiple long tendrils, stemming from a flat and miniscule central point.
When moving around as a larva, Cardians are able to join together all of their tendrils into a worm or snake like structure, enabling them to slither through the swamp's muddy waters or the arteries of their host more effectively.
Their skin appears mostly in a reddish gray, as it is partially see through, and therefore lets the blood it fed on shine through quite prominently.
After a Cardian's incubation phase inside of a living host is complete, their tendrils would have grown in size reminiscent to the length of the distance between the host's heart to the ends of their closest appendages, as well as in width close to the aorta, superior vena cava, and pulmonary artery.
Stretching out and clogging up its host's arteries with this expansion in width and size, the Cardian's tendrils would then cause major organ failure to occur, leading to an uncomfortable and painful death of its host.
Since the blood of its host would now no longer be enriched with oxygen for the Cardian to feed on, its next step would be to begin extracting itself, as well as the heart it is still nested in, from the dead body of its former host. And with that complete its incubation, where it would now drag its fully grown body by its elongated tendrils, whilst also wearing the heart of its first host as a gruesome shell for a slight bit of protection.

Behavior and Social Structure:

Mainly driven by the instinct to feed possess Cardians no form of notable social structure or ability to think.
They mainly appear to roam aimlessly around and constantly look for a suitable host to feed on, whilst also not showing any signs in regards to their own safety, as they seem to recklessly attack everything they sense has fresh blood flowing through their veins.

Role in the Food Chain:

In the Living Decay, Cardians actually rank quite low within the food chain, as most creatures native to this toxic swamp seem to either possess skin too thick for the Cardian to penetrate, or blood too toxic for the Cardian to thrive in.
For beings coming from outside the Living Decay though, like creatures roaming the Lands freely, or adventurers from the Guild, Cardians are known as an extremely dangerous and life-threatening health hazard.
As not only are these parasites able to easily infiltrate the bodies of most beings who aren't native to the swamp when coming into contact while still being a larva, they are also capable of emitting a deadly disease known as Blood Pest when entering their host's bloodstream with their tainted tendrils.
Able to sense both body heat and movement through an array of sensory nerves along their tendrils, Cardians will mainly hunt based on these two attributes. Where in their larva state, they would simply just try to find a soft spot for them to infest their host's body. While in their fully grown state, they would try to wrap their elongated tendrils around their prey and search for the bodies major arteries to penetrate and anchor to.

Special Abilities and unique Physical Traits:

While the body of a Cardian appears to be rather soft and squishy, the tips of their tendrils are actually quite hard and sturdy, which enables them to easily penetrate the skin of most creatures.
The tips of a fully grown Cardian's tendrils also seem to be equipped with a rather large amount of electrocytes, which are able to emit shocks strong enough to cause heavy muscle spasms. Or even paralyze its prey if the Cardian chooses to enhance these shocks through a form of primal Channeling.
Speaking of Channeling, a mysterious occurrence was also being observed where if a fully grown Cardian has latched itself onto its prey, the arcanic energy around them would not only slightly increase in amount, but also in purity. With the exact reason as to why remaining unknown.

Additional Insights:

Whilst a true cure for Cardian infestation remains currently unknown, there is one experimental solution to try and treat those who have just been infected by one.
This treatment however only promises a very slim chance of actual success, whilst also bearing a great risk of either combusting into an ethereal flame at the slightest misstep, or suffering severe and long-lasting cardiac dysfunctions and inflammations if it succeeds.
The proposed treatment, first performed by the swamp's alchemist Samachar, is done by the forbidden practice of Infusion, where the blood of the infected would be drastically heated up to the point just before the ignition of an ethereal flame, in order to try and kill of the parasite before it can reach its host's heart.
Any attempt of this experimental cure after the Cardian has already started its incubation phase would most likely just end up with its body remaining stuck inside of its host's heart ventricle, causing permanent irritations or even severe dysfunctions.
It is therefore strongly encouraged for adventurers planing to head out into the Living Decay to always take proper precautions, like equipping some strong and sturdy armor to cover their entire body. Or putting on some special ointments in an attempt to disrupt the Cardian's sensors and try to basically turn invisible to them.