Hundun

A type of spirit hailing from East Asia, specifically China, the Hundun can be considered one of a few 'spiritual plagues'.
A possessive spirit, it must take control of a person to inflict any action upon the living world. When it does so, it does not fully enter it's prospective target. Instead breaking a section of itself off within the targets soul. This splinter slowly, but surely subsumes the victim, until it completely covers their inner being.
When that is done, the newly created Hundun will split into two. One remaining inside the victim, the other going out to search for the next closest person to repeat the process. Left long enough and an epidemic of catastrophic proportions can rapidly form.
Those possessed by the Hundun will have a large shift in their personality over time. Even the nicest person will become wild and brutish, doing things that their friends and family would never expect. Theft, damaging of property, and other hoodlum-esque actions at first. Escalating to more serious crimes; extortion, assault, murder, etc.
The victims can, if they are strong enough, fight against the possession. By denying the thought that Hundun attempts to put forward as the victims own, they can stunt or halt it's growth. There are some religious sects and monks who willingly allow themselves to be possessed to prove their own righteousness and inner strength, crazy as it might seem.

Basic Information

Anatomy

They have no definitive shape, and most certainly nothing that could be confused for a body. They simply exist as a black, cloud-like mass to those with the ability to see spirits. Ever-roiling and shifting. Despite it's lack of form, those that observe it say that they can 'feel' it's gaze on them. As if it was staring in abject rage at all those around it. Simmering, eternally, over life itself.

Growth Rate & Stages

Once an individual has been implanted by the Hundun, the time it takes to completely subsume it's host varies greatly. If the infected individual is one that was already on the path the Hundun whishes to perpetuate, it can take months or even a few weeks. If the infected was a paragon of virtue, who resists every vice and nasty impulse with easy, it can take years or even decades. Or, as mentioned, they might be able to resist it entirely. If that's the case, the splinter will simply remain, straining against the good nature of their host until they are exorcised.

Additional Information

Geographic Origin and Distribution

Hailing almost entirely from east Asia, to the point that cases describing an outbreak of Hundun outside of the country can be counted on one hand, and even those are close enough that they could be said to just be ones that ranged surprisingly far.

Average Intelligence

The Hundun itself doesn't seem to posses much intelligence, instead relying on the intelligence of their host to do the tasks they wish to happen.

Perception and Sensory Capabilities

Despite the previous description of what people who observe the Hundun feel, it does not seem to actually see in the traditional sense. Seeming to simply drift between where it senses life. Should what it comes across be unsuited for it's goals, it will simply float to the next closest source, like a bee tasting flowers.

Scientific Name

Larua Licentia Cor Meum

Lifespan

Indefinite

Body Tint, Colouring and Marking

A black, reddish coloring suffuses their amorphous form. Like creamer in the darkest coffee.