Equipped with dual Metal Storm Howitzers consisting of sixteen 155mm barrels, the Behemoth is the pinnacle of GDI's artillery divisions. Designed over several years in tandem with GloboTech and fielded shortly before the Emerald Peak Massacre, its state-of-the-art design would later be used as the basis for GDI's Mammoth Walker. The initial practical tests were overseen by Colonel Nigel "Gunner" Grant, the GDI liaison in charge of the Behemoth's trial.

The history of the Behemoth came from some of the Field commanders who sented complaints of even though the Buckshot's are efficient Artillery walkers, the MLRs don't have enough heavy armor or the firepower to assault a NOD. So Colonel Nigel "Gunner" Grant and some designers began working on a new type with Artillery.

The Metal Storm  Howitzers are inspired by the Roman candles used for fireworks and as such, that was used for the weapons of the Behemoth.

After testing was done on the Behemoth and it proves successful during the original tests, GDI command approved of the Massive artillery and had ordered more to be made and produce for every GDI force, even using the model without the Howziers on it for other uses.

While the Behemoth is armed with an incredible payload and encased in heavy armor plating, it's helpless against aircraft and enemy attackers that have managed to get within its minimum range, as such it is advised that a protective escort be provided during combat operations.

Because of the high cost of tech and supplies, only three can be constructed at a time.