"You speak truly, Zeratul. An unseen hand moves them. We must be on guard."
- Zeratul and Artanis(src)
Amon's Brood (or Amon's Zerg, or the Amon Brood) was a zerg brood that served the fallen xel'naga Amon. They were subjugated from former feral zerg groups outside the control of the main Zerg Swarm such as those left on Aiur after the Overmind's destruction. Its ranks included several older zerg strains no longer used by Kerrigan's Swarm, such as the airborne queen, the scourge, the guardian, and the corruptor, along with more recently developed breeds, including the viper and the swarm host. It did not possess brood lords or any of Abathur's specially-evolved strains. Amon's hybrid frequently led these zerg into battle.
Reclamation of Aiur
Amon's Brood made its first appearance on Aiur in 2506 during the Daelaam's first attempt to retake the planet. In the early stages of the invasion, the zerg behaved like uncoordinated ferals and posed little threat to the protoss armies. However, as the protoss continued their advance across Aiur, the zerg they encountered started showing signs of intelligence and coordination. The protoss eventually discovered that the hybrid led these zerg.
On Artanis's instructions, Zeratul attempted to leave for Korhal to retrieve the Keystone, only to discover that his Void Seeker had been destroyed. Moments later, Amon's zerg ambushed him. Zeratul's stalkers killed the attackers, but Zeratul was concerned because the zerg in the area were supposed to have been eradicated. Zeratul sent his stalkers to the nearest Nexus point to warn the protoss stationed there. After fighting past zerglings and mutalisks, the stalkers reached the Nexus point, only to find it abandoned. Selendis then warned Zeratul that a number of templar, including Artanis, had mysteriously vanished from the Khala. While searching for these missing templar, Zeratul's forces had to fight past more of Amon's zerg.
After Amon corrupted the Khala and seized control of the majority of the templar, he deployed his brood alongside the corrupted protoss against Artanis and his remaining followers, who were attempting to escape Aiur in the Spear of Adun. Artanis's forces held off the enslaved zerg and protoss long enough to escape.
Fall of Shakuras
Later, Amon's Brood launched a direct assault on Shakuras through the warp gate from Aiur. Accompanied by Void thrashers and hybrid, the Amon brood swiftly infested the planet, decimating the Nerazim Shadow Guard and laying waste to their cities. The protoss under Artanis arrived just in time with the Spear of Adun to engage the zerg and evacuate the surviving Nerazim to the arkship. Rather than allow Amon possession of the planet, Matriarch Vorazun decided to destroy Shakuras and all the zerg upon it. In accordance to her plan, Artanis lured as many zerg and hybrid to Shakuras as possible before overloading the xel'naga temple and destroying the whole planet, killing all the zerg and hybrid on it.
Assault on Endion
Amon's Brood later infested the surface of Endion and tried to prevent the Daelaam from reactivating the Purifiers. When Artanis's forces deactivated the stasis grid surrounding Cybros, Amon's zerg and hybrid quickly invaded the station and tried to destroy the core matrix. However, the Daelaam awakened the Purifiers, and with their aide, cleansed Cybros of Amon's zerg. Shortly afterwards, the Purifiers activated Cybros's purification cannon and annihilated the zerg on the surface of Endion.
As the End War raged on, Amon's Brood were deployed across multiple battlefronts, and allied commanders rose to meet them. The brood used its Nydus Brood and Winged Brood to fight the forces of the sector.
Return to Aiur
Amon's Brood appeared for a final time when the Daelaam invaded Aiur again. These zerg attempted to stop Alarak and Vorazun, and later Artanis, from disabling Aiur's psionic matrix. Amon's zerg also attacked the Spear of Adun, preventing the ship from supporting Artanis's strike teams. Despite the brood's efforts, Artanis, accompanied by his Nerazim, Purifier and Tal'darim allies, succeeded in destroying the three key structures powering the psi matrix, thereby delaying the Golden Armada's return.
With Aiur temporarily cut off from the Golden Armada, Amon used his zerg, along with hybrid, void shades, and corrupted protoss, to defend his host body. Once again, they failed, and the protoss destroyed Amon's host form. As the protoss prepared to use the Keystone to extract Amon from the Khala, Amon sent his remaining zerg, and later the corrupted Golden Armada against Artanis's forces in a furious, desperate effort to destroy the Keystone. Despite the zerg and corrupted protoss's overwhelming numbers, the unified protoss held off the attackers long enough to activate the Keystone and remove Amon from the Khala. At Artanis's urging, the newly-freed templar severed their nerve cords, banishing Amon back to the Void. With Amon gone, the Daelaam reclaimed Aiur.