A Gefjun Disturber is a device created by Rakshata Chawla to disable Knightmare Frames. It does this by disturbing the chemical and mechanical processes of the Knightmare's Sakuradite and interior computers and gears preventing movement, which also disables all sakuradite-based technology. In addition, the field blocks the motion of hadrons, radio waves, and microwaves. The Lancelot Conquista was developed with countermeasures that provide a partial defense against it. This resistance has been implemented on later 7th Generation Knightmare Frames. Other than this, it has shown several other uses such as controlling the blooming effect of hadron-based weaponry as well as a defensive shield against hadron and MVS-based weapons.
The Gefjun Disturber was initially developed by Rakshata during her internship in the Imperial Colchester Institute, but it was merely in a theory form at the time. It is first field-tested in 2017, in a skirmish in Shikine Island.
This was the earliest known working version of the Gefjun Disturber, which was deployed in a circular formation. Though it was a success, its range and operational time was still limited. In 2018, Rackshata developed a more practical and mobile version of it called the Gefjun Net.
These portable versions of the Gefjun Disturber are equipped with the Black Knights' Air Glide System technology. Another version was later used by Lelouch to cripple the operational capacity of the Tokyo Settlement. this version no longer follows the Gefjun Disturber's circular allignment and each device works as an individual unit. It is also has a far more prodigious range disabling the Concession area with only a limited number of them.
Lelouch, who had several of these devices built onto a train, uses them to paralyze Jeremiah Gottwald by interfering with the Sakuradite in his bionic parts, and used it to disable a majority of the Tokyo Settlement.