What is Therianthropy?

Therianthropy is a morphogenic retrovirus that introduces a symbiotic primal spirit into the host. The virus starts by changing the host's genetic structure in order to create a framework for the symbiont to attach to. Therianthropic viruses can take from one to three weeks to fully incubate, with minor variations between the strains. During incubation, the host may note an increase in regenerative effects. In extreme cases, the aging process begins reversal before the symbiont "awakens", though the longer one survives as a therian the closer one comes to their physical peak.

The bite …

Examination of living therians shows that there are "viral sacs" located just below the sinuses in the cheek bones. They are called viral sacs because, similar to poisonous snakes, the sacs hold reservoirs of super-viral infused blood that the therian secrets

A bit of history:

According to Mage Lore, the first therian was the son of an anima red mage (mage who could transform into animal forms) who attempted to force his child to posses mage-gift despite being born with out. Lacking the proper affinities, both in parent and child, the magic twisted and transformed the child into an animal. Much tinkering later, the child was able to transform, but could perform no other magic. However, he ceased aging when he reached his full growth, coming to outlive his parent by several centuries before dying a violent death. He was also stronger, faster, and had heightened senses compared to how he was before his father's gift.

Additionally, the son found that the longer he held animal form, the more of the animal's thinking he brought back with him (which is NOT usually the case with anima mages!). He grew lonely, watching friends and family age, sicken, and die, until one day he retreated into the form of wolf. His younger brother attempted to comfort him, but soon the brother also fell sick with age. One day, the brother reached out to the son, who, feeling the wolf's frustration and his own loneliness, bit the out stretched hand.

The brother bound up his hand and left the son to his worry. However, within weeks, the brother began to look younger and the sicknesses of old age retreated. The therian's people rejoiced and asked for the son's bite themselves so that they might grow young again. The son, thinking that this was a great idea, agreed.

Long and short, within a few months most of the people bitten by the son became therians. Most of the new therians could only take one animal form and it seemed to be based more on their personality than any other factor.

Over the millennia, the therianthropic viruses have evolved. They have become distinct strains. Most newly turned therians are only able to assume the primitive form of the strain - canids assuming wolf form, felids beginning with one of the great cats, etc. As the therian gains control of his shifts, he is able to take on the more domesticated animal forms.

On a rather interesting side note, even if the beast half is naturally solitary, all therian strains are social strains.

Therians (super)naturally bulk up when they shift, gaining between 30 and 50% body mass. A therian that has gained a high level of mastery over the shifts can also down shift mass and take on a smaller form.

The symbiont (which therians typically refer to as the "Beast" or the "Other") is able to force the therian to shift forms in cases of extreme stress. The longer a therian goes between voluntary shifts, the more likely the symbiont will be able to force a shift. Generally, every week after 6 weeks without shifting doubles the likelihood of a forced shift.  During forced shifts, the symbiont is in control of the body and may even completely block out the host's rational spirit. Seeing as how the symbiont is very primitive in comparison to the human half of the therian, this is not considered a good thing.  For this reason, most therian tribes will pick a moon phase and set up a communal shift. It is a standard that newly turned therians within the tribe are required to attend in order that the more experienced therians can keep them in line if the symbiont takes control. While the symbiont is able to force shifts on the therian, the therian is said to be "moon tied."

On the Plus Side, or the Benefits of Therianthropy

As noted in the History Sidebar, therianthropes die violent deaths. Not one single therian in recorded history has died from "natural causes" (i.e. mundane illness or physical deterioration). Part of this is because the therianthropic viruses continually reinforce the host's immune system. The how is as yet undetermined, though there are theories that the viruses assimilate every foreign incursion into the host body.

As for physical deterioration, on one hand, therian cells stay "in play" far longer than mundane cells. Whereas a mundane human will generally have replaced every cell in their body within a seven year cycle, therian cellular replacement cycles are about triple that.

The Path to Ascension

Ask most therians what their goals in life are and at least nine out of ten will include Ascending somewhere on that list. So, what is Ascension?

If you ask Joe Average Therian, he'll tell you Ascension is conquering the Beast. It is true that Ascended shifters need no longer worry that their symbionts will attempt to take control of their bodies. However, according to the Ascended shifters, conquering the Beast is the hardest path to Ascension and usually the most likely to be fatal as the symbiont reacts to being "conquered" as it would to any dominance challenge from a perceived equal - it fights.

All shifters are very aware of dominance. It is a central point in their life.

[more to be filled in later]