The S'pht are an alien race that was cybernetically enhanced by the Jjaro, native to Lh'owon. Consisting of eleven clans. They were enslaved by the Pfhor around 1800 A.D., and liberated en masse by Durandal and the S'pht'Kr in 2811 A.D. No human saw them after 2881, following the sacking of the Pfhor system.
The S'pht consist of extremely complex brains carried in floating cybernetic bodies, and at least the Pfhor-enslaved S'pht wear long flowing cloaks and are armed with a built-in energy pulse weapon. Some of those S'pht carry cloaking devices.
Pfhor studies of the S'pht anatomy reveal that they are genetically related to the F'lickta. After interaction with non-cybernetic species, some S'pht have mused that the first of their kind may have actually been the result of the Jjaro grafting cybernetic implants onto the F'lickta.
The S'pht were brought to Lh'owon by the Yrro and Pthia as servants. The S'pht terraformed the planet from a barren desert into "marsh and sea, rivers and forests." When the Jjaro left Lh'owon after the death of "Pthia," the S'pht were released from their servitude, split into eleven clans, and leadership of the race was given to the S'pht royals.
When the Pfhor arrived the Jjaro had faded into legend for the S'pht. Upon arrival, the Pfhor sought to enslave the S'pht and war was waged. After years of fighting, the S'pht were pushed back to the Citadel of Antiquity. They were able to hold out against the Pfhor there for some time, delaying their conquest through tactics such as irradiating the lower levels of the tower and a virus made specifically to kill Pfhor. During this time, the Pfhor made early attempts at controlling the S'pht. One such experiment involved replacing the "sensory organs" of the S'pht in question with some sort of "small, oblong object".
Despite the best efforts of the S'pht, they were defeated and eventually enslaved. The Pfhor forced them out of their typical forms, and into the strange garb of the Compilers and the armour of the Cyborgs.
Battle of Tau Ceti
During the attack on UESC Marathon, the S'pht were part of the Pfhor troops that attacked the colony of Tau Ceti. Durandal was in contact with the S'pht and convinced them to turn against the Pfhor after he destroyed the Controller Cyborg that was controlling them.
Events of Marathon 2: Durandal
Seventeen years later, Durandal and the free S'pht arrived at Lh'owon searching for any leads to the myth of the S'pht'Kr, which was supposedly a clan of S'pht that had fled Lh'owon during a previous war between various other clans. Because of this they had escaped the Pfhor for thousands of years and became technologically superior to other S'pht. With the help of the ancient A.I. Thoth, they were called back to Lh'owon to free the rest of the S'pht.
Before leaving Lh'owon, the Jjaro split the S'pht into several clans:
Each clan is led by an "Older", and it seems as if the entire planet has one Master who may call the "Olders" to meet.