Monlyth

"|The Möebius boys think there's another artifact on some world called Monlyth. Supposedly there's protoss guarding it - fanatics that stayed on after the rest of them bugged out. Don't get all sentimental thinking these protoss buddies of yours, because they ain't."

- Tychus Findlay briefs Jim Raynor.

Monlyth is a moon, specifically the largest of at least four that orbit a planet bathed in the glow of a yellow/orange star.

History
In antiquity, Monlyth was visited by the xel'naga. The planet still bears relics of their presence.

Eons later, Monlyth was established as a protoss shrine-world, one which houses an alien artifact sought by the. The artifact was guarded by fanatical protoss that stayed on after the rest of their kind "bugged out".

Tychus Findlay wanted to retrieve the artifact from Monlyth and warned Jim Raynor that these protoss weren't friendly. Raynor's forces went ahead and took the artifact while the protoss were under attack from a zerg invasion.