What is gellar field failure?

A gellar field is a fictional technology used in the Warhammer 40,000 universe to protect ships and individuals in space from the dangers of the Warp, a chaotic and unpredictable dimension. When a gellar field fails, it can result in catastrophic consequences such as the emergence of demonic entities aboard the ship and the corruption or possession of crew members.

Gellar field failures often occur due to the degradation of the technology over time, exposure to intense Warp energies, or sabotage by enemies. The consequences of a gellar field failure can be devastating, ranging from the loss of the ship and crew to the spread of Chaos corruption to nearby planets or even the entire sector.

Due to the high risk of gellar field failure, Imperial ships are equipped with backup systems and protocols to prevent or contain these events. The Adeptus Mechanicus is also tasked with maintaining and repairing gellar fields, and some factions within the Imperium seek ways to improve or replace this technology altogether.