The Gesserits (members of the Bene Gesserit Church, which is divided into Orders based on function) are an exclusively female organisation who's primary goal is the genetic manipulation of bloodlines over thousands of years to produce ideal specimines of humanity, and eventually to unlock the maximum potential of the human mind, body, and magic. Dating back before recorded history on the island of Namiri, THe Gesserit order has evolved from a mere religion, into a formidable manipulative force.
The Gesserits essentially control every aspect of Namiri life, even the Emporor, who is, albeit unknowingly, merely a pawn in their master plan, as his family has been for millenia.
Gesserits Insignia

Leader
Reverend Mother of Hidden Rank:
Currently, the Lady Inirya Zhoul. The Highest Rank within the Gesserit Church, and final authority in all matters. Essentially a godess in her own right the Reverend Mother of Hidden rank combines thousands of years of memories, knowledge, and experience into one young, and healthy body (relatively speaking). Capable of inhuman feats of will, She is a match for any ten Wizard Grandmasters alone, in addition to being able to call on combat skills of Sisters of different classes than herself. In short, she is able to be anything she wishes or needs to be, whenever she wishes or needs to be it. Killing her would require an army… and then some.
Fortunately, the Reverend Mother does not use her powers lightly: Preferring to remain on Namiri, within her Cathedral Spire.
She is only seen and known personally by the Reverend Mother Council: She grants audience to no one else. Ever.
It is rumored she has vast powers beyond comprehension… although this might just be common hear-say.
The Gesserits rank system:
Initiate: New members, ussualy girl-children, who are undergoing education. (ages 8-15)
Acolyte: Initiates that have begun testing of Prana-Bindu, Magic, and academics studies. They will either pass all of these tests, or die. Every Acolyte, as an initiate, is paired with a female initiate who is chosen to be tailored to be a perfect freind. all Acolytes will invariably bond deeply with their counterpart, on a level greater than sisterhood. Then, as one of their final tests as an Acolyte, they must fight their counterpart to the death, in a no-holds barred combat. Should they refuse to do battle, they both are killed. (Should an Acolyte pass, but not be Grade-A materiel, they will be sent off to become Savants, which will be discussed next.)
Savants: Savants are often reffered to as non-cloistered Acolytes: All Acolytes not on Namiri are of this sort. They have been deemed unfit to continue further in study, due to genetic limitations that are quite out of their control. Savants fill rolls as aids, helpers, and all-purpose servants of upper ranks, though some are still sent to deal with important tasks from time to time, generally in groups with higher-ranks overseeing.
Adept: Those Acolytes that pass their testing (ussualy around the age of 16) begin adept training, which ussually lasts several decades. Adept training consists of mastering and developing the skills that are taught in the Acolyte phase, then specializing based on each individual's talents. No Adepts are allowed to leave Namiri during this time, nor are they allowed to scry in an unauthorized fashion. Violation of any dictate of the Order results in death. After undergoing more testing, should they be ready, they undergo full initiation into the Gesserit Sisterhood.
Sister: The rank of Sister is attained through undergoing the Initiation. This test last over year, and is a closely gaurded secret. Any Sister is quite immune to mind-reading, Mind-Rape, and other mental effects such as mind-control, influence, and are highly resistant to bluffing, and intimidation. Sisters may be specialized into different roles, including the unique Truthsayer type which are immune to being lied to. Sisters are then utilized for many many years in varied service to the Sisterhood and it's programs, being assigned to Orders based on function.
Reverend Mother: Reverend Mothers are Sisters of the second highest rank: essentially unquestionable in any regard, they are above reproach. Their bodily mastery is complete, they are skilled spell casters on par with any that walk the lands of Naelvich, and their stregnth of will has progressed to the point that they can will individual cells within their bodies into certain actions: practically freezing (and even reversing age), immunity to poisons, disease, and mental illness. They are also capable of the unique ability to use their Wisdom modifier in the place of Dexterity or Stregnth when making attack rolls. Reverend mothers can die of old age, but only at extream periods of time. When they die, they often choose to be ritually mind-raped, and their life experiences and memories are combined into the person of the current Reverend Mother of Hidden Rank. In this way, no Reverend Mother truely dies, and the power's of the Reverend Mother Superior (or of Hidden Rank) are multiplied with every passing Reverend Mother.
The Hectors: The Hectors are clones of a great warrior of ages gone bye: Created through secret arts, they are excellent fighters. Existing in three varieties, the Hectors serve as the only male appendage to the Sisterhood: believed to be a fore-runner project to their ultimate goal: the Auerien Messiah.
Hector (Clone): Lesser clones of the great Hector, the are skilled fighters on par with most any single elite trooper in Naelvich. They serve as retainers and gaurds to Gesserits, primarily among the Missionaria Protective of the Order of the Grey.
Hector Victorious: one of ten elite clones of Hector enhanced by actual Gesserit training (to a limited extent), he is assigned and fanatically loyal to a single Reverend Mother. reffered to as "Victor" by the Mothers, Victor is equal to entire phalanxes of common footsoldiers.
Hector the Great: Hector the Great is the original Hector. He is a living legened, with his twin waraxes of lightning. His armor is ancient, and nearly impervious to harm. He was last reported to have slain a thousand men single-handedly in a bloody Namirian uprising two centuries prior. He does not appear to age. He is the loyal servant (and supposed lover) to the Reverend Mother of Hidden Rank. He also does not leave Namiri without great reason.