A jorōgumo has three forms – human, spider, and hybrid. The human form is unremarkable and not easily distinguished from a real human. In spider form, they take the form of a giant golden orb-weaver. A jorōgumo in spider form can grow quite large, reaching a leg span of 35cm or more.
The hybrid form is a mixture of humanoid and spider. A jorōgumo in hybrid form has a human trunk and head, with eight spider legs, of which six sprout from their back while the remaining two are attached to their abdomen, which transitions smoothly to a bulbous spider’s abdomen (replacing the human pelvis) and includes a spinneret for producing silk. The placement of the legs means that the human torso is kept horizontal, facing downwards; the head and neck are shifted back a little to allow the jorōgumo to still look forward without straining. The mouth is framed by spider-like pincers. The arms are entirely human (so a jorōgumo in hybrid form has a total of ten limbs).
Most jorōgumos are female; about one in a hundred is born male. A male jorōgumo is about two-thirds the size in spider form, rarely growing more than 25cm in leg span. In human and hybrid form, there is no appreciable difference.
Birth and Childhood
A jorōgumo can reproduce either as a spider or a human, though they most often choose the latter method. Whichever method they choose, the offspring are locked in that form for the first five years of their life.
Spider-form jorōgumo spawn large numbers of offspring, and reach full size as a spider over the course of their first year, if they survive that long. Most don’t. Once they have reached full size, they must remain a spider for another four years, during which time they don’t change at all.
Human-form jorōgumo only have one or two children at a time, and they age as normal humans.
After gaining the ability to transform, both types continue to age normally in human form for another ten to twelve years; the spider form continues to remain unchanged during this time. The actual onset of puberty can vary from age 10 to as late as 15, after which they take two to four years to develop fully into an adult human form.
At around fifteen or so years, the jorōgumo’s aging process slows dramatically. At fifteen, they look more or less like an eighteen-year-old human, and they still look pretty much the same by age thirty, but even so, they are slowly aging. The actual rate varies quite a bit and can even change over time for a given individual, but on average they age around ten times slower than a human; so at age sixty, they still appear to be in their early twenties. (At this rate, they’d have to be around 350 years old before they appear to be in their fifties.)
Their spider form starts to lose its colouration at around a hundred years of age, though their hair in human form remains black (or rarely another colour) for much longer. The yellow parts go silver first, over the course of twenty or thirty years. Only once there’s no yellow remaining do the black parts of their spider form also begin to fade into a sort of muddy greyish-brown.
The limit of a jorōgumo’s natural lifespan is uncertain, but it’s known that they can live for at least five hundred years.
A jorōgumo favours a diet of meat, though they are also partial to rice and will readily eat vegetables if they are available. Most jorōgumos specifically favour the meat of humans, though there do exist those who have sworn off that in the name of peaceful coexistence.
As previously mentioned, a jorōgumo can transform into three different forms. Each form is fixed for the individual, meaning that they can be recognized in any form if you know precisely what to look for. For example, the exact pattern of yellow and black banding on their legs as a spider is unique to each individual. The hybrid form combines recognizable traits from both human and spider forms.
They have no overt powers in human or spider form – to all intents and appearances, they seem to be an ordinary human or spider. In hybrid form, however, they are able to produce very thick strands of silk which can be weaponized to bind or ensnare. Like a normal spider, they can choose between different silk types, including sticky and non-sticky variants.
In all forms, a jorōgumo is immune to all toxins that affect humans. This doesn’t precisely mean they are immune to poison, only that anything toxic to a human is not toxic to a jorōgumo. They also seem capable of eating anything humans eat, meaning that human food also does not contain toxins for them.
Their fangs can produce a variety of different venoms. It’s rare for a jorōgumo to actually produce the venom of their namesake, as it’s too weak to significantly affect humans. Their normal poison is quite a potent neural inhibitor, with a small does causing full-body paralysis in adult humans within just a few minutes. A significantly larger dose is required to kill. However, a jorōgumo is also capable of mimicking other poisons, especially ones that they have ingested. For example, some have been known to hunt with poisons closely resembling belladonna or monkshood.
In addition to poisons, a skilled jorōgumo can also produce antidotes in their fangs. This is more difficult, but if successful it can be quite a bit more effective than standard methods whether scientific or alchemical. For example, the eventually-fatal dependence effect of a gancanagh’s poison has no known alchemical cure (though it can be treated), yet a skilled jorōgumo can cure it with their fangs.
Society and Culture
Jorōgumos are solitary creatures, typically living in abandoned houses or remote caves. They often prey on livestock or humans, which they’ll wrap up in silk and store for weeks, paralyzed. They usually dismember their prey first and eat the limbs, daubing silk over the wounds so they don’t bleed to death. Only later do they feast on the main body.
Though jorōgumos can get along well enough with their own kind, they usually avoid contact if possible. A single jorōgumo can plot out a fairly large territory in which they hunt, and others usually avoid intentionally encroaching on that territory.
If a female jorōgumo chooses to mate, it will usually be with one of her intended prey. Instead of paralyzing him from the beginning, she allows him some measure of freedom for awhile. Only later does she bind him up as food. Most men who have escaped a jorōgumo’s clutches were those considered to be potential mates; for the same reason, women and girls are far less likely to escape.
While male and female jorōgumos do occasionally mate, the males tend to avoid this due to the fact that they would also end up as dinner. If a male jorōgumo sires a child, it will usually be with a human woman. As with any fae-human union, such a child is completely human but retains some vestige of its father’s powers.