It is Aztersil's most common virus, though it is not common enough to be considered, normal. Each virus has it's own power, abilities, and form. By itself, the virus cannot function. Its form is nothing but a sort of sludge like material. Once it attaches to a host the virus will insert it's own DNA into the host's chain, destroying the host in the process. In only a few minutes, the virus will have taken control of the host, and the body will not longer look as it originally did, but will take on the virus true form. This form is always a biped, and no sisul has wings enough to fly, though gliding is acceptable. Their eyes can be any colour, but their pupils are ALWAYS white, though also, any shape of pupil is acceptable.
There is no real gender difference between the sisul, though some are obviously female, and others obviously male. They do not mate, or any of such actions. Their form of reproduction happens when they leave a host. The sludge or mist formation that makes up their lone, host less forms commonly divides or splits in two, creating a second sisul.
They are mostly wonderers, providing information and services to all those around them. Some can blend into society so well, because their true forms do not appear much different from that of a human or an elf. Others are quite obviously the sisul viruses, for their forms may have long claw/fingers, some sort of growth, jutting jaw and a mouth full of sharp teeth, or any number of oddities.
Sisul tend to be overly cocky. Many tend to have a sort of graveyard humor. They are not the type to needlessly go out of their way for someone, though they do act in a very gentlemanly manner towards life.
They are very cocky creatures, seeming to always have a constant grin on their faces. Others are very wary of the sisul, for every disease's host must die at some point, and the sisul must be able to move on to another host.
It is incredibly difficult to kill a sisul. Though there are ways to do so, it is near impossible. Sisul, as many tend to forget, are not the form you see before you, but the virus that flows in the form's veins. If you tick a sisul off, and destroy it's form, which is susceptible to physical attacks, the sludge that makes up the virus is still alive and will either take over your form, or take over another's and come after you.
The physical form of the sisul is susceptible to physical attacks, but the pure virus itself is very difficult to kill. Within the pure virus lie the personality and the being that makes up the form. Only fire, or powerful heat can kill the virus. Though the sisul can stand heat when it has a physical form, or a host, the pure virus, non-host, cannot survive intense heat.
The sisul can have many different abilities, but most of these fall into the physical understanding. They can, for instance, depending on the sisul, lengthen and sharpen their fingertips to make their hands something along the lines of butcher knives in a fight. It is unknown exactly what all abilities fall into the hands of the sisul, but most all Aztersilians know that they do not want to get into a fight with one.
All of the Aztersil races and beasts are susceptible to this virus.