Known among their own simply as Arachni, these changing creatures have the ability to turn themselves into spiders. For some it's a single spider with the mass of a medium sized car that get's the benefit of increased speed and a fortified exoskeleton, making it more difficult to be penetrated. For others it's the ability to "melt" themselves into a thousand normal sized arachnids, each one controlled by a main tarantula that houses the brain and thoughts of the actual person. This main tarantula is protected at all costs, because while the lesser spiders can be destroyed with little issue (usually causing a limb to be gone when the person forms back into its' human phase), if the tarantula is destroyed the person dies, as that is the spider that holds the beings consciousness.

The spiders have good healing abilities, capable of growing removed limbs over the course of three days. During this time period they must stay in a cool place where they won't be disturbed. It takes significant concentration, and while interruptions won't halt the process altogether, they will significantly slow it down. Minor wounds, such as scratches, torn muscles, etc. can be healed in a day, but once again, the Arachni must be in a cool place with few distractions.

Arachni are a naturally secretive people, who do their best to keep their gifts hidden from anyone and everyone, save the few they consider true friends, or those who have proven themselves worthy of the knowledge. Due to their nature, were-spiders are adept at the arts of infiltration and information gathering. They tend to use whatever means are available in order to get the information they require, having less of a conscience by societal standards. Possessing a "by-whatever-means-possible" mentality, these beasts are right at home in the dungeons and dark places of the world, and are often called upon to "interrogate" prisoners of war for valuable information.

The spiders don't tend to hold grudges, believing that if they are in the way of someone's goals that they should have removed themselves from the situation. The exception to this is killing. If a being kills a were-spider, it falls to the next male in the family hierarchy to avenge that death with a vengeance; the most accepted method is to drain the offender of blood, leaving a husk. Doing otherwise is considered weak, and often leads to extradition from the nest. However, if information concerning the deceased is presented and a conclusion can be reached that the spider did deserve said death, it becomes a point of pride for the rest of the beasts in the family if the next male avoids unnecessary bloodshed, putting his emotions aside for the greater logical conclusion.

Though legends say otherwise, the Arachni generally have no need to drink human blood, capable of surviving on animals just as easily. A few that have gone insane in past times have brought on the rumors of giant spiders feasting on the blood of humans, but in their society to do so is considered a great blasphemy, unless there is no other food source around or they are taking the life of one who killed their brethren. Also, every three centuries there is a spider born who's only sustenance is that of humanoid blood, but this being, instead of a curse, is considered a blessing, meaning prosperity for its' lifetime. The other spiders treat it nearly like a god, catering to its' needs without much of a second thought.