|This page contains spoilers for:||Warrior Brood (Novel)|
The machine was the result of a programme initiated by Inquisitor Lord Brutius Parthon in order to create an anti-Tyranid weapon, sometime after the Ultramarines defeated the alien hordes at Ichar IV. Seeing the destructive power of the Hive Fleets, Parthon created a research facility under his oversight on the planet Herodian IV which was staffed by members of the Adeptus Mechanicus. Shortly after this event, Lord Parthon encountered the fleeing and wounded Craftworld known as Iyanden which was located in the Ultima Segmentum where he struck a deal with the native Eldar. In exchange for their aid in developing a powerful weapon against the Tyranids, he would not reveal the location of their Craftworld to the Imperial Navy. The Eldar agreed to this arrangement and Lord Parthon began assembling the necessary components for his weapon.
It resembled a simple chair, integrating Tyranid biological material that created an organic bond with its occupant. With this working in conjunction with the psychic amplifiers of Eldar design, the machine was able to boost the psychic potential of its host to incredible levels. Thus, it served as a weapon against the Tyranids by creating a disruptive signal that attacked the Hive Mind where it severed synaptic nodes and caused confusion within the swarm by using its own relay system. As such, the weapon assaulted the Hive Mind from within its own organic command structure. It also had a secondary unwanted side effect, which was that it served as a psychic beacon to the Tyranids and attracted their ravenous forces.
This weapon remained fixed at its location until a small Tyranid splinter fleet from Hive Fleet Kraken emerged and attacked the planet Herodian IV. The defending Imperial forces signaled for the aid of the Mantis Warriors who quickly moved to protect the world from the Xenos threat. However, they were overwhelmed and managed to make a hasty retreat to the research facility on the world. There, Librarian Shaidan uncovered the Grendal-machine and learnt it was a weapon, whereupon he activated it for use against the Tyranids. At first, the alien invaders fell back and were slowly being culled by Imperial forces but shortly afterwards, the Tyranids attacked with renewed strength. Not only that, they seemed to possess knowledge of the Codex Astartes and other Imperial tactics which the Xenos used to plant traps that massacred any military force that stood against them. Unknown to anyone at the time, this was actually the result of the Grendal-machine's activation, as Inquisitor Derteg Grendal's mind was broadcasting all his knowledge to the Hive Mind.
In order to secure the weapon, Lord Parthon dispatched his protégé, Inquisitor Kalpysia. To that end, she co-opted the aid of the Deathwatch under the command of Captain Quirion Octavius. Masking her mission, Kalpysia claimed that the location of the secret research facility was the Brood Nest of a Tyranid Hive Tyrant. After the first failed sortie, the Kill-team managed to reach the surface of the planet and penetrated into the surface, where they reached the abandoned Mechanicus base. Once inside, the Deathwatch learned of the Grendal-machine, which Inquisitor Kalpysia insisted on saving. During the attempted recovery, the device bonded with Kalpysia and turned her against the Deathwatch until she was blasted out of a Thunderhawk along with the machine, which was detonated remotely, killing her as well as the construct. Captain Octavius did not report the find of the Grendal-machine and simply reported back to Inquisitor Parthon that the destruction of the Hive Tyrant was achieved, though the Inquisitor Lord later ordered an Exterminatus on Herodian IV in order to wipe out any further evidence of his activities on the planet.