RISE OF THE SOCIETY; THE SHAMANS AND SORCERORS:
With the establishment of basic group organization and building skills allowed the rise of the tenets of religion, cvilization, the village, and more advanced language and farming. New forms of control were now needed beyond that of the Alpha Male. Quasi-poltical-religion was now employed, ushering in the era of Shamanism, the first recorded mystical power using individuals. Also, the most powerful to this day of the Light Side warriors, as they are the base to all future religions.
It is also the time of the rise of the Sorcerors, the enemies of the Shamans and their quasi-government/religion. Sorerors are the first warriors to oppose the oncoming civilization of mankind, attempting to use it for the superior purposes of harbouring the Dark Side (which they had just newly discovered.) However, they were the weakest of the Servants of the Darkness (or "Dark Side Warriors") because many of their techniques were based on those used by their Light Side counterparts. The Sorcerors were banned from the early communities if discovered, so severe secrecy was adopted. Still, they started a tradition, a movement in the making.
CIVILIZED CONTINUATION OF THE BATTLE; THE SAMURAI AND NINJA:
Japan is where the next recorded resurgance of the Servants of Darkness, or the "Sith," can easily be seen. Civilization was now very established, and so were its protectors, the model for Star Wars' Jedi, the Samurai. Policing the empire, their injustices soon led to the rebellion of farming communities who turned to the Dark Side for seperation and protetion. Thus the Ninja eventually evolved, who are the model for Star Wars' Sith. They worshiped aspects of the Darkness which they called evil spirits, as well as throwing out the useless notions of honor used by the Samurai, adopting any technique whatsoever that gave them an advanatage. With the rise of the Ninja comes the official rise of what is considered to be the "Sith Order". However, the Ninja, having thrown away much of the secrecy established by the Sorcerors in exchange for greater power, were soon destroyed by the Samurai.
POWER AND THE DARK SIDE:
The reason for the constant reappearance for the Servants of the Darkness is man's desire for power and the superiority of the Dark Side over the cvilized, intolerant Light Side. As long as the Light Side warriors exist in their many forms (religious mainly, but also political) the Servants of the Dark Side will not cease to try and overthrow them to install the superioity of the Dark Side, and control civilization to make it as unintrusive as possible.
The Dark Side is much more powerful, however has always been wiped out by the evil Light as the power the Sith have is envied by the lower castes created by civilzation. (These lower catses would normally have been wiped out by nature, but medicine, welfare, and other tools of Light's civilation allow them to live. But they are not capable of the Dark Side.)
Secrecy is again employed by the Servants of the Darkness, but they are scattered and not unified. Power draws them inevitably together though, as it always does, and the Dark Side is preserved in the "underculture" establishment (like the gangs, mafias, mobs, and drug cartels, as well as those countries which apose America's world order through tyranny and nuclear development.) Power and the Dark Side is impossible to wipe out, as there will always be those of the Sith Caste who know that all seek power, and they should seek it the best way possible--through the Dark Side.
THE ETERNAL SITH AND THE MODERN SERVANTS OF THE DARKNESS:
The Sith have always existed. The Silosian Sith Order is not so much new as it is ten thousand years in the making--ever since the Sorcerors of old. It is in this tradition that the Silosian Sith Order has risen. It is time for the Darkness to rise once more... permanently. "Once more the Sith will rule the [world]... and we shall have peace." -Darth Sidious