Glacius has been a Protoss Empire research station since before the Great War. On the planet was a facility where the Khalai developed new purifiers, a technology that was made secret to all but the highest ranking protoss officials. Additional research on advanced robotics and solarite were done within the facility, and it was defended by orbital cannons and sentries.
During the End War, Hierarch Artanis moved to retrieve the prototype purifiers and use them as a weapon against Amon and his forces. However, the Tal'darim under First Ascendant Alarak attacked the facility, and began to use their mothership's displacement beam to purify the facility. The Khalai scientists were evacuated, but the Daelaam was forced to race against the displacement beam in order to retrieve the container holding data on the new program. They succeeded, warping the container aboard the Spear of Adun. The rest of the facility was purified.