Ku'Gath was once a Nurgling sitting upon the shoulder of Nurgle. Whilst Nurgle was mixing his most virulent toxin ever, Ku'Gath tumbled from his nesting place into the cauldron, where he took a great draught of the filthy contents and swelled with its power. Invigorated, Ku'Gath drank and drank until the cauldron was nearly empty and he had grown into a Great Unclean One. Nurgle laughed at the antics of his Nurgling, who had become the embodiment of the perfect disease that had been bubbling within the cauldron. Ku'Gath, however, realised that he had robbed his father of the greatest disease ever concocted; and has since been wandering the universe, searching for the perfect ingredients to recreate the toxin for Nurgle. He also captures those whom his diseases corrupt and take them back to his lair, where he can observe their degeneration more closely.[3a]
In 927.M41, Ku'Gath was summoned on the Agri-World of Curwen at the head of the Daemonic Legion. A Grey Knights strike force arrived, and Justicar Anval Thawn led a force into the very heart of the Daemonic horde to avoid encirclement. Ku'Gath swallowed the Purifier whole, but Thawn detonated his weapon inside the Daemon's throat and burst from its body. Ku'Gath was slain and banished back to the Warp.
Ku’Gath appears again in 998.M41, when intervention of Justicar Styer and his Grey Knights in attempts of Inquisitor Malia Orbiana to find on the planet Squire's Rest of Sanctus Reach biological weapons against Orks, led to the manifestation in reality the Bonewrack disease - once lost Ku’Gath’s infection. Later the Grey Knight managed to defeat Ku’Gath and his horde of Plaguebearers and expel daemons to the warp. Ku’Gath himself was defeated by the blow of Librarian Gared when his Nemesis Greatsword bisected Ku'Gath's head.
In 111.M42 during the Plague Wars, he appeared on Iax leading seven hosts of daemons, trying to destroy it because of its conversion to a hospital-planet, something that caused death to Nurgle's gifts. During the war on Iax he was given a portion of Nurgle's own cauldron, which he attempted to use to concoct a brew that could slay Roboute Guilliman. Ku'Gath's plan later came to a head at Parmenio, where the Daemon failed to kill Guilliman who instead slew his lieutenant Septicus.
Unlike his fellow Great Unclean Ones, Ku'Gath is a sombre creature. He is also studious and observant, all the better to create the perfect disease. He is pessimistic and prone to worrying, bemoaning Nurgle's plan on Iax as likely to fail. Unlike most Daemons of Nurgle he despises music, and violently demands that the twisted bands of the Plague God keep silent while around him.
Ku'Gath rides atop a palanquin carried by straining Nurglings, and loaded with the paraphernalia of his mobile laboratory. In battle, Ku'Gath uses the opportunity to conduct his field tests, unleashing clouds of spores and bacteria that could wipe out whole armies.
- 1: Battle Missions, p. 17
- 2: Codex: Grey Knights (5th Edition), p. 16
- 3: Codex: Chaos Daemons (6th Edition), p. 51
- 4: Sanctus Reach: Maledictus (Novella) by David Annandale, Chapter Ten
- 5: Dark Imperium (Novel) by Guy Haley, Chapter Sixteen
- 6: Dark Imperium: Plague War (Novel) - Chapter 3
- 7: Warhammer 40,000 8th Edition Rulebook pgs. 154-159 - War Zone: Ultramar