The Trih xeem is a powerful weapon that can be used to force a star to go into an early super nova. Originally created by the Jjaro, it is now used by the Pfhor to end slave revolts.
The trih xeem was used on two occasions, once against the Nakh (a "client" race of the Jjaro) and their rebellion six thousand years before the events of Marathon 2: Durandal, and once against the Drinniol.
The Trih xeem is a main plot point in Marathon: Infinity as the Security Officer races to prevent the Pfhor from activating the devastating Trih xeem and releasing the dormant W'rkncacnter.