Juujin: A female exclusive human subspecies, possessing superhuman capabilities, a heightened libido, physiological alterations of varying degrees, and an inclination towards pack mentality.
Biology: Genetically, juujin DNA is 99% identical to human DNA, and many of their more extreme differences have no understandable genetic cause. There is a great deal of speculation and debate as to whether or not juujin are of the same or a different species than humans. Much of this is fueled by the fact that there is no record of a juujin becoming pregnant, though no one has been able to prove conclusively if this is a genetic incompatibility or if the process that transforms a human into a juujin results in sterilization.
Physiology: All juujin possess human features to one degree or another, though exactly how human in appearance they are varies greatly from individual to individual. Presently about 30% of all juujin are completely indistinguishable from regular humans when not actively using their powers. A further 20% are only marked out by possessing skin, eye, and/or hair pigmentation outside of the human norm. 25% of juujin possess an/several additional and/or altered physiological trait(s), most commonly expressed in the form of animalistic claws, teeth, ears, eyes, or noses; the addition of a tail or wings; stripes, spots, or other markings; and/or small patches of fur, feathers, or scales covering up to 25% of the skin's surface. 15% of juujin are even less human, possessing complete or nearly complete coats of fur, feathers, or scales, and/or alterations to the basic human form itself, particularly in regards to the skeletal and muscular systems, and the size, layout, and/or addition/substitution of internal organs. The remaining 10% of juujin are not even humanoid, and possess only a passing semblance of the human form.
Regardless of their over all degree of human appearance, juujin possess an unearthly beauty, something beyond mere looks that no one has yet to clearly define. Juujin possess an uncanny ability to appear attractive and sexually appealing to the society they belong to, and are nearly universally sexually desirable.
All juujin are much more resilient to injury and illness than normal humans. Anything short of completely destroying a vital organ is unlikely to kill a juujin, even without medical aid. The juujin circulatory and nervous systems are both much more resistant to failure caused by injury or illness, largely due to having a network of vessels and nerves as opposed to the branching layout of the human systems. This makes the juujin circulatory and nervous systems much more capable of circumventing damaged areas to ensure continued operation, as well as allowing multiple redundancies to minimize the chance of tissues becoming oxygen deprived or suffering interruptions in communication with the brain. Juujin are also capable of operating with very low blood pressures, further reducing the effects of blood loss.
Juujin do not scar, nor do their bodies accumulate damage. A juujin's body will heal injuries back to their pre-damaged state, including repairing nerve damage or regenerating lost appendages; even brain damage can be repaired. Juujin therefore can not be crippled or disabled, and there have been cases of disabled teens thresholding (see below) into fully able bodies. Juujin also heal nearly three times as quickly as humans.
Likewise illness and disease effect juujin far less severely than they do humans. The juujin immune system is far more resistant to pathogens and harmful chemicals, and is capable of completely flushing their bodies of contaminates. It is exceedingly rare for a juujin to die from disease or poisoning, and even serious cases such as AIDs or radiation poisoning will typically clear up in a few days to a week, with the juujin healing ability readily repairing any damage.
It should be noted however that this advanced healing ability is a function of a juujin's S2 organ (see below); without which a juujin's healing rate and degree drop to human level, though they still retain an inhuman resilience gained from their physiology and immune system . This is also why removal or destruction of the S2 organ is permanent.
Threshold: The process by which a human female turns into a juujin. The trigger for the transformation has been linked to the end of puberty, but the method and means by which the girl becomes a juujin is currently unknown. There are no known definite indicators that a girl will or will not change into a juujin, though genetics seems to play a role. If one sibling thresholds, any sisters she has are likely to as well, within the 80% range in most locations. In twins or triplets, the number jumps to over 95%. Generally the transformation takes place between the ages of 16-21. The percentage of girls who turn into juujin varies somewhat from location to location, but between 65% of all girls going through puberty will transform. The length of time a transformation takes is largely a matter of how much and what degree her physical form is changed. The process is however very rapid by conventional standards, taking a mere 1-6 hours for completely human looking juujin, 4-12 hours for juujin with minor deviations, 12-23 for those with moderate alterations, and 19-46 hours for the extreme cases. The process itself is not generally painful, but is often uncomfortable. Frequent symptoms displayed before, during, and after the change include headaches, nausea, dizziness, fatigue, weakness, swelling, dryness of the mouth/throat/skin, rashes, and fever.
Mentality: The vast majority of juujin retain the personality and intellect they possessed while human, though the stress of dealing with their new form, powers, and the personal and social changes that can occur from the event do tend to leave a mark on the juujin's psyche, especially in the cases of the more inhuman looking juujin. A small percentage of juujin are driven to insanity by the transformation, though whether this is a result of the change itself or an inability of the juujin to cope with her situation has yet to be determined.
Libido: A juujin possess a very high libido by human standards, and has a very strong need for sex that is both physical and mental in nature. The longer a juujin goes without sex, the more and more it impairs her ability to think and function rationally. A sex starved juujin can be readily compared to a drug user suffering from withdraw. However a juujin can not be detoxed or weaned off of sex.
The longer she goes without sex, the more wild and uncontrollable she will become, and the more prone to violence she will be. A juujin is capable of sinking into a mindless, animalistic state if denied sex long enough. In this condition, commonly referred to as feral or wild, a juujin's only priority is sex, and she will do whatever she thinks is necessary to get it. She will not discriminate or reject any possible partner, nor will she be in a rational enough state of mind to keep herself or her powers under control. The mortality rate for mating with a feral juujin is around 75%.
This issue is further exacerbated by the fact that only a human being can fulfill a juujin's need for sex. Masturbation or sex with another juujin can satisfy a juujin's desire for sex, but not her need for it. In fact, either case only increases a juujin's need for sex. Though she may be momentarily sated immediately afterward, she will need sex to avoid going feral/wild sooner than if she had abstained entirely.
Exactly how long a juujin can go before her mental faculties begin to degrade and how long she can maintain any self control depends on the willpower of the individual juujin. On average however a juujin begins to feel a need for sex after 3-5 days, begins to lose focus after 4-9, begins to seriously degrade around 7-13, and generally loses complete control after 11-16 days.
It should be noted that these numbers only represent the time frame in which a juujin's need for sex begins to impede her ability to function normally. Even when they do not technically need it, juujin are almost always eager and willing to have sex, and completely sating a juujin's sexual desires is sometimes most people would consider a monumental effort. Emotions: Juujin are far more prone than humans to forming emotional attachments to their sexual partners, and become close emotionally far quicker. With a regular partner, a juujin can become utterly infatuated in as little as a week. Once they reach this stage, commonly referred to as bonded or linked, juujin are prone to becoming subservient to their partner.
The degree to which this influences their behavior can vary wildly, and seems to largely be an issue of force of personality and will of the juujin. Some juujin become completely and utterly obedient, willingly or not, and will promptly jump to follow their partner's orders, and even consider suggestions as commands to be immediate carried out. On the other end of the scale, some juujin can manage to remain independent and can ignore their partner's wishes, though even in the most strong willed of juujin, this can be an effort, and it is something they have to give constant attention to maintaining.
Many people generally misunderstand just what bonding/linking entails, due to the wide range of effect it has over various juujin. The most common misconception is that a bonded/linked juujin is not only obedient, but loyal as well. While some juujin do indeed becoming fawning, willing slaves, most tend to display a similar level of regard and respect for their partner as any human female would, which is to say that there is a very wide range of possible behavior possible.
Unfortunately, some juujin, like some human women, do end up in bad relationships, which are greatly exasperated by the bonding/linking process. In some of the worst cases, the juujin in question does become a literal slave to her partner, unable to disobey them or leave them, and it has lead to some troubling cases of whether or not to treat the juujin as comparable to an addict in need of help.
Bonding/linking is capable of forming between a juujin and any human(s), male or female, but not for other juujin. This not to say that two juujin can not become fond of each other, but that they will do so in a more human fashion and time frame.
While juujin are capable of jealousy, it is a different sort than that displayed by humans. Juujin for the most part are indifferent to their sexual partners sleeping with someone else, but only so long as they do not feel they are losing the attention of their lover. As such a juujin will gladly share a lover, but will react badly, even violently, if they feel they are being cut out of their partner's life.
