The Ziranii, or "Caste of the Soul", is a secret society made up of members of various psionic and quasi-psionic races (including a few minor human races) that have officially been eradicated or converted by the Vilani during the Consolidation Wars of the Ziru Sirka. Psionics have always been persecuted by the Vilani culture, even before their expansion into space, as psionics have traditionally been associated with the "warrior gods" (Ancient warbots) that fought one another on Vland until 20,000 years ago.
While some Ziranii members speculate that a secret society similar to the "Caste of the Soul" may have existed to unite and protect those few Vilani psionicists that may have existed in Vilani pre-stellar history, no evidence has ever been brought forward to support this theory. In actuality, the Ziranii started as an underground movement during the Consolidation Wars of the First Imperium, when several psionic races (including a minor human race) sought to avoid death and persecution during the "Vilanification" of their cultures. Massive near-genocidal attacks by the Vilani greatly reduced the numbers of these races, and the survivors made extreme efforts to integrate into Vilani society. Originating within the coreward reaches of Diaspora sector, all but forgotten by history, the Ziranii movement slowly maneuvered to positions of power in the rimward sectors controlled by Sharurshid.
By the point of the Ziru Sirka's first contact with Terrans at Barnard's Star (2096AD), the Ziranii secret society had spread its membership of a few thousand over three sectors, occupying positions of importance in preparation for a daring move. The Ziranii had begun a plan to move beyond the rimward borders of the First Imperium, and establish a safe haven many parsecs beyond the reach of the Vilani oppressors. A staging area had been selected on the rimward border, and operations had begun under the guise of the research and development outpost of Ikugi (Solomani Rim 1926, known to the 3I as Barnard's Star.) The plan took a major shift when, less than a decade into preparations, the Vilani were encountered by another major race, humans from the nearby Terra system (Solomani Rim 1827.)
The meeting was held in secret in the year 2094AD (Terran reckoning), with first contact made by a telepathic member of UNSC Advanced Intelligence division, a Terran governmental agency secretly conducting psionic research for "intelligence purposes." The United Nations Security Council, having detected radio emissions from the new colony, utilized the recently developed Waven Hyperspace Shunt drive (jump drive) to engage in a clandestine mission of First Contact. The AdvInt agent, detecting the presence of a talented Ziranii telepath, engaged in negotiations with the local Ziranii Council leaders, and both sides left the table with the beginnings of a new plan. After conferring at the Provincial Council at Dingir, the Ziranii determined to utilize the Terrans to cover their own actions, developing an unsteady allegiance with the United Nations Security Council Advanced Intelligence division. Carefully orchestrating the initial interactions between Terrans and the Ziru Sirka, starting with an official First Contact in 2096AD, the Ziranii played the two cultures against one another as they continued to prepare for their colonization rimward of both the Terrans and the Vilani. The increased trade and diplomatic missions proved a successful smoke screen for the movement of Ziranii provisions and people to Ikugi. In exchange for technical information, the Ziranii's AdvInt allies kept Terran intervention to a minimum, although a few individual pockets of resistance grew against the machinations of the Ziranii and AdvInt.
The Barnard Incident of 2110 (also referred to as the Canberra Massacre) escalated a state of war between the Terrans and the Ziru Sirka, throwing the Ziranii's carefully laid plans into disarray. An all-out surprise assault by their AdvInt "allies" on the gathered Ziranii members at Ikugi in 2117 reduced the numbers of the secret society by almost two orders of magnitude, and the few remaining members scattered to the stars.
Over the decades and centuries that followed, the Ziranii slowly grew in strength, and worked against the Terran invaders. Members of AdvInt waged a secret war against their once-allies, the Ziranii, and both organizations strove to wipe the other out. The success of the Terrans in forming the Rule of Man drove the Ziranii deep into hiding. Most Ziranii Councils were eventually discovered and destroyed during this troublesome period, but a small membership did survive. Using centuries old techniques of hiding amongst an anti-psionic society, the Ziranii blended into the background, and bided their time, content to control from behind the scenes.
Various Councils survived the Long Night, and reestablished contact through their concentration on centers of political power. Although some dispute has arisen between a few of the Councils as to the direction and leadership of the Ziranii, the general concensus granted a majority of intergroup authority to the Capitol Council, as the seat of greatest political power resided there for the Third Imperium, and for the future goals of the Ziranii.
During the early years of the 3I, the Ziranii subtly supported and promoted the presence of official Psionic Institutes, trying to build a pro-psionic stance within Imperial society. The actions of other secret organizations, anti-psionic in nature, has hindered the Ziranii progress significantly. Great strides in changing public opinion were made during the 700's, until public opinion went radically anti-psionic with the Psionic Suppressions. Over the last few centuries, the Ziranii have retreated into hiding once again, again driven nearly to destruction.
Time has healed the old wounds, the membership has grown once again, and the newer members are looking for new directions, new goals, new frontiers. Perhaps the Ziranii Dream might be better pursued on the Imperial frontier. Perhaps the Domain of Deneb, with its proximity to the Zhodani Consulate, might prove to be an area worthy of development. Perhaps the Solomani Rim, once home to the traitorous AdvInt, might prove of benefit in the goals of the Ziranii. Perhaps...but that is a story yet to be told.
(Additional note: The Psionic Suppressions could also have been directed against the Ziranii, who might have secretly been working with the Zhodani to bring about a pro-psionic shift in Imperial society. However, since the Ziranii tend to keep to the conspiratorial shadows, nothing has ever been mentioned of them in history texts, and they are all but unknown to the general public.)