The Walkers of the Abyss
Somewhere in the deepest recesses of space lurks a dark intelligence. A singular, malevolent mind that seeks only one thing:
Expansion. Its origins are a mystery but its purpose is clear. It uses a most vile method to expand itself. A virus. Specifically, a retrovirus that engineers its host to serve in a variety of roles meant to carry expansion into the endless void.
These infected are known as the
Walkers of the Abyss, a term derived for the region of space from which Infection is believed to have issued. Though it is deep space, a massive nebula (the 'Abyss') dominates the area. This nebula is composed largely of gases that give it a distinctly blue, deep ocean like color.
The Walkers sole purpose in existence is to spread Infection and expand. They are not entirely in control of their own minds and much of what they do is guided by the
Master of the Abyss. What the Master
is is not something that is fully known, but some of the
Avari elders (see below) are convinced that he/she/it may have once been a
Progenitor (the Avari term for Ancients).
The Master possesses many ways of spreading infection. The virus can engineer infected hosts into a myriad forms. The most prevalent are simply known as "
the Touched". This is the most direct way that infection spreads, in the typical, "28 Days Later" fashion. This form of the virus spreads through contact of body fluids, including blood, sweat, saliva and seminal fluids. Despite this very basic form, this shape of Infection is the most virulent and hardest to kill, as it happens to pop up in the most unlikely of places with great frequency.
Another form the hosts can take is a
Carrier. These are not merely people who are immune, as no one is actually immune, since the virus is not entirely biological and has its own "ascended being" like properties. It is, in most cases, a rather random occurence, wherein an infected person (infected in the same way as the Touched) will carry a version of the virus meant to infect not organisms, but technology. When the host comes into direct contact with said technology, the virus infects it and slowly finds ways to propagate itself through it.
The most insidious form of host is the
Acolyte. It is not known how they are infected (though quite creepily, it is known that some are "born" from infected fetuses). These individuals seem to be, on the surface, largely unaffected by the virus and are able to carry on with normal behavior (whereas a carrier will often demonstrate some behavioral oddities). That is, until they are "awakened". At that point, they become true physical manifestations of the Master, where he almost directly controls their behavior.
It is these Acolytes which are most often used against targets of special importance or against people who are otherwise highly resistant to normal infection. Their jobs vary, but their number one goal is to remove impediments to Expansion. Directly channeling the Master's vast intelligence, they are often seen to be invulnerable to conventional attempts to stop them and can only really be stopped by the best humanity has to offer.
The
Tau'ri first encounter an Acolyte on R1X080, the first stargate humans have independently gated to in another, non-Ori/Ancient/Asgard galaxy (
Andromeda). She appears to them as a sickly, starving young girl whose village has just been wiped out by the Avari (a lie, of course). When an Avari claiming to be a survivor of her attack claims that it is in fact this little girl who is the culprit, the Tau'ri cannot believe it and allow her to escape with them to the
USS Heracles (BC-304-7).
They are never seen alive again.
Their last transmission comes to the SGC via an unusual carrier wave. It also comes packaged with all the information you've read above. It is the Avari and they issue the Tau'ri a simple but icy warning:
"He knows you. He knows everything about you. And he is coming..."
Three weeks later, the IOC sends the
HMSV Hood (X-305) on a straightforward mission. Stop infection. Stop it at all costs.
ALL costs...
"Don't let him touch you. Never let him touch you. For once he has hold of you, he will never let go. He will make your mind a tomb and bury you alive in it." - Avari Proverb
P.S. - Four gold stars to anyone who can guess who the Avari may be, based solely on the above and on their name.