S'pht'Kr are the 11th S'pht clan and left Lh'owon long before the Pfhor arrived and enslaved the S'pht. The majority of the story in Marathon 2: Durandal revolves around Durandal sending the player to various locations on Lh'owon in order to search for the S'pht'Kr.
Though powerful, the S'pht'Kr are not much larger than the average human. Unlike the more familiar S'pht Compilers, the S'pht'Kr have a bulbous, glassy sphere and three short appendages; one curling up underneath them like a tail, and the other two coming down at their sides. Like their other S'pht cousins, the S'pht'Kr hover, as they have no appendages to walk with. Inside of the spherical "helmet" rests a very complex brain.
It is unknown for certain if all S'pht'Kr appear as the ones seen in Marathon 2 and Marathon Infinity. The schematic text (seen to the right) indicates that the "S'pht'Kr Elite Guard" are a special cadre of S'pht'Kr.