Glassing

Glassing, also known as planet cracking or purification, was a protoss war technique used to destroy all life on planetary surfaces, usually to eradicate the presence of the zerg. A purification attack was carried out by ships firing massive energy beams to sterilize a planet's surface. Carriers were equipped for this purpose and could project energy from their bows, while motherships and possibly other large ships such as void rays could also be used. Glassing could disperse most of a planet's atmosphere and release magma onto the surface by burning through the crust, and minerals on glassed worlds acquired unique properties. The technique was central to the protoss doctrine of containing the zerg, and its use against inhabited Terran Dominion worlds during the Great War made the protoss feared across the Koprulu Sector.

Method and effects#

A purification attack was carried out by ships firing massive energy beams that sterilized a planet's surface. Carriers were equipped for the task and could project energy from their bows, and motherships, along with possibly other large ships such as void rays, could be used as well. The process could disperse most of a planet's atmosphere and, by burning through the crust, release magma onto the surface. Minerals on glassed worlds afterward acquired unique properties. A small number of beings could survive a glassing by sheltering deep underground, as a handful of terran marines did at Chau Sara.

The Great War#

Before the Great War, a disgraced executor seized a Protoss Empire facility known as The Rock. The Empire prepared to purify the installation, but Praetor Fenix subdued the rebels before the base was destroyed.

When the protoss discovered the extent of the zerg infestation of Chau Sara, Executor Tassadar reluctantly ordered his expedition's ships to power up their weapons and destroy the planet, firing on both terran settlements and other points. At least two ships obliterated most or all life on the surface, though a small number of marines, including Andre Madrid, survived by hiding underground. Shortly after Chau Sara, the protoss fleet purified the planet of Gystt.

Tassadar avoided attacking the next infested world, Mar Sara, until after the terrans had evacuated, and several hours after the escape his forces sterilized the planet. When a large battle between the zerg, the Terran Confederacy, and the Sons of Korhal broke out on Antiga Prime, Tassadar's forces purified that world as well after a particularly devastating zerg attack. His fleet then arrived at the Confederate capital world of Tarsonis, which had been besieged by zerg drawn there by the Sons of Korhal's psi emitters. Lieutenant Sarah Kerrigan, a ghost, believed the protoss had come to destroy the planet, and forces under her command defeated them. The protoss did not purify Tarsonis, and protoss and zerg continued to fight on the planet's core continent. Tassadar's refusal to burn the terran homeworlds was among the reasons the Conclave later condemned him.

Interbellum and the Second Great War#

An attack took place under mysterious circumstances on the ice world of Braxis sometime after the Great War, and the planet refroze in the years following. The protoss also partially purified the world of Urona Sigma in 2502.

During or before the Second Great War, the zerg established a presence on Taurus IV, infesting a Dominion force sent to investigate. A protoss executor intercepted the terrans' distress call and requested the aid of the Golden Armada, and protoss on the surface held the zerg at bay long enough for the Armada to eradicate them from orbit. During the conflict proper, Doctor Ariel Hanson intended to relocate several hundred colonists to a world called Haven, ideal in all aspects except its closeness to protoss space. When the zerg infested Haven and protoss warships entered orbit to purify it, the protoss recognized the Hyperion and asked Jim Raynor to help in the purification, while Hanson asked for time to complete a cure. Raynor chose to help Hanson defend the colony, angering Executor Selendis, who sent a powerful mothership to purify the terran colonies. Raynor managed to evacuate most of the colonists before his forces destroyed the mothership.

The End War and after#

During the End War, the corrupted Golden Armada was sent by Amon to purify all worlds within the Koprulu Sector, opposed by the Terran Dominion, which could only slow its advance. After Hierarch Artanis activated the Purifiers in Cybros, an executor activated the purifier cannon on a warship and purified the surface of Endion of all life, removing the threat of Amon's brood there.

During the Defenders of Man Insurgency, the Death Fleet led by First Ascendant Ji'nara moved on Tyrador IX to destroy the Defenders of Man, and on coming out of warp the fleet's void rays began to purify the hive clusters on the surface. By 2511, the Terran Dominion had begun constructing bunkers buried beneath the reach of protoss incineration.

In the era of tenuous peace, Overqueen Zagara set about regrowing worlds previously destroyed by protoss purification using the adostra, beginning with Gystt. During the One-Day War, Hierarch Artanis favored purifying Gystt due to the zerg presence there but agreed to delay, swayed by Emperor Valerian Mengsk, who argued that it would shatter the fragile peace with the Swarm. Most of Artanis' ships, including a mothership, several carriers, and void rays, had their weapons prepared to initiate the purification, but after the investigation into the zerg attacks concluded, the procedure was called off.