The initial origins of the Gravitational Beam Emitter are unknown, though it is heavily implied to predate the City itself. It appears to be a Safeguard weapon, as numerous agents are seen using instances of them, but they are known to have been used by the earlier members of the Silicon Creature's cult.
It is known throughout the entire City, feared by some and coveted by others.
Killy does not seem to remember where he aquired it, though Sanakan claimed that he stole it from the Safeguard forces at one point.
May have been invented by the same creator of the gravitational swords.
The GBE fires condensed graviton energy, with the beam emitted literally pushing away the atoms of whatever is in it's path; the pushed atoms crashing back together cause large explosions, creating additional damage than the initial gravity beam.
Unlike most weapons, the GBE does not seem to run out of ammunition, as it appears to draw it's power from the user itself. Because of this, the gun has a form of limiter installed on it, preventing it from using too much energy and killing the user; this limiter can be deactivated by the user if they choose to do so.
Despite it's basic appearance, it's inner mechanisms are apparently incredibly complex; so much so that even the Bio-Electric Corporation, one of the most advanced companies known in the City, could never figure out how to replicate it.
There are four charge levels of fire, each one far more powerful than the last.
Level 1 requires almost no charge and can be fired rapidly (depending on the energy level of the user). At this level, the range of the weapon is 70 km.
Level 2 requires several seconds of charge and is notably more powerful, creating massive holes in it's target. Killy, who can fire the gun one level 1 with minimum recoil, is knocked backwards from the force of the kickback.
When charging up to Level 4, the weapon will actually open up. In this state the recoil is so powerful that it will actually tear off the limb holding it. Firing in this state requires a high amount of energy.
- Tsutomu Nihei has stated that the effects of the weapon are so powerful that if it were to ever be fired from Earth's surface, it would have devastating effects on the climate and atmosphere of the planet itself.