This page contains information regarding Star Trek: Discovery, and thus may contain spoilers.
The Followers of Kahless were a Klingon group, which included the Guardians. They awaited the return of Kahless at Boreth. However, the monastery they occupied on the planet was not only built to house them, but also to protect and guard the rare time crystals native to the planet. (TNG: "Rightful Heir"; DIS: "Through the Valley of Shadows")