The origin of the Great Unclean One Ku'gath is that he was once merely a tiny Nurgling, dancing carefree upon the vast body of his loving father, Nurgle, in the time before time began. At that time, the loving father was carefully brewing a cauldron of the ultimate plague, known as the "Divine Plague," a blight potent enough to corrupt the very stars.
In an inadvertent game, the tiny Nurgling stumbled and fell into the boiling cauldron. The moment he plunged into the hot ichor, he subconsciously swallowed a great gulp. Immediately after, he began to drink without stopping, as if the poison were the only sweet nectar in all existence. When it finally ceased, the crucible, carrying the essence of endless ages, was drained to its last drop.
Awakened, Ku'gath was consumed by boundless terror. He realized he had devoured the masterpiece his loving father had been brewing since the beginning. He trembled, awaiting the inevitable thunder of wrath.
Yet Nurgle is revered as the "loving father." He possesses infinite tolerance and curiosity for his family. Nurgle looked upon the child who had consumed all the Divine Plague and was rapidly transforming from a tiny Nurgling, swelling and expanding into a Great Unclean One.
The father's forgiveness did not ease the burden in Ku'gath's heart. The cauldron of the gods, which he had drained, became his eternal guilt and obsession. From then on, Nurgle's Garden housed an unclean one who was always serious and smiled no more. He carried out all the Father's commands with a piety that bordered on redemption, forever feeling that he could never do enough.
To atone for that ancient "mistake" made after becoming a Great Unclean One, Ku'gath persistently travels the material universe, plundering all forms of life, trying to distill them in his plague laboratory and recreate the lost "Divine Plague."
Such paranoid behavior was incomprehensible to the other Nurgle daemons and Nurglings, who preached the casual spread of plague, but Ku'gath remained undistracted, endlessly perfecting his impossible "masterpiece" on a path of solitude.
"After hearing Ku'gath's origin, what do you feel?"
Nix looked at Mortarion, who was deep in thought.
"A troublesome enemy..."
Mortarion said in a grave tone. "Such a paranoid existence is often the most dangerous. What He holds firmly in his arms is likely the unfinished 'Divine Plague.'"
He could already imagine that when he fought the mountain-like daemon, the plague would erode his body and will.
Are you sure you're not talking about yourself?
"At that moment, it all depends on you, brother."
Mortarion said solemnly. Faced with the Divine Plague, the only countermeasure he could conceive were Nix's unfathomable skills.
"Understood. But your opponent is not him."
Nix's gaze pierced into the distance. "Ku'gath is mine. You go and fulfill your destiny."
He raised a hand and pointed to the fortress atop the peak, now completely overgrown with the strange flora of Nurgle's Garden, transformed into corrupted ruins.
"I will. Wait for my return."
Mortarion's promise rang out. He could already see Necare on his throne, his foster father—all traces of his former rule were erased, leaving him isolated. The next moment, Mortarion vaulted from the camp and headed for the mountain peak and his fateful final battle.
Nix watched his brother's figure rapidly recede, shook his head slightly, and turned towards the horizon. With the extraordinary vision of a Primordial, he could clearly see the walking corpses known as the "Plague March" and the countless daemon legions of Nurgle, wearing ghastly smiles, slowly and inexorably approaching.
They seemed to be spreading the "Gospel" of the loving father to every corner of Barbarus.
"How troublesome..."
Nix whispered, but the corners of his mouth curled slightly. "However, what I've prepared will finally come in handy."
He immediately gave orders, his voice regaining the calm and efficiency of a commander:
"Lasker, you and the other veterans who have completed the transformation will each lead a fireteam to conduct long-range suppressive fire."
"Kashtan, go and bring all my 'Poison Gas Detonators.' Remember, every last one."
A pleasant yet dangerous smile bloomed on his face. The ultimate weapon he had created had finally found its perfect stage—the toxic mist of the entire planet had been concentrated above the enemy army due to Ku'gath's arrival, and at this moment, there was no fear of blowing the Liberators' camp sky-high.
Soon, Brother Ba carried a massive glass jar nearly as tall as himself; the amount of vibrating liquid within it was enough to completely annihilate a significant portion of the so-called Nurgle daemon army.
Nix's smile grew ever more open. He was also the "Space King" who once crossed the sea of stars, and when it came to the creation of "all life," he had never lost to any group of tech-priests under his command. He was absolutely confident he would enjoy a grand fireworks display that would leave an unforgettable impression on the uninvited "guests" before him.
"Remember... leave a good review!"
Before he finished speaking, the air around Nix suddenly grew heavy. It was not a warp-based psychic fluctuation, but a more fundamental and arrogant exercise of authority, a rule of power directly invoked. A brilliant golden current emanated from the depths of his being.
Countless golden arcs of lightning, visible to the naked eye, connected between his palms and the glass jar, emitting a low hum. Space itself seemed to become pliable clay, and in an instant, a "slingshot" formed from an invisible giant, made of pure gravity, appeared.
Where the glass jar was, space suddenly sagged; the jar itself, blessed by the maddening spin of this golden magnetic field, was compressed and accumulated with enough potential energy to tear the sky.
The next moment, he waved his hand, and the "invisible slingshot" was suddenly released.
The glass jar, as tall as a man, was hurled, transforming into a golden streak that pierced the green canopy and streaked towards the center of the Plague March.
At the moment of impact, time seemed to freeze for a single frame.
First, a blinding pale light consumed everything, instantly vaporizing the distorted smiles of countless Plaguebearers and daemons. The toxic mist, gathered here by Ku'gath and covering the entire world, instantly became the most deadly fuel.
An emerald-green, terrifying firestorm, reaching several kilometers in height, soared upwards, forming a gigantic, ever-expanding mushroom cloud that symbolized pure destruction. The shockwave radiated outwards like a physical tsunami, tearing through the front lines of the Plague Daemon army like dead leaves and flinging them away.
The front of the Liberators' position could even feel the scorching and toxic wind—this was precisely the "fireworks" Nix had anticipated.
However, this feast of destruction lasted less than ten seconds.
At the very heart of the firestorm, an ominous, viscous, dark green light stubbornly flared, and it was Ku'gath. The mountain-like giant shadow stood unmoved against the enemy's wind.
An incredible, blasphemous scene unfolded: the destructive flames and discharges began to change color sharply—from blazing white and emerald green, they rapidly dimmed and fouled, transforming into a sickly yellow-green and burnt black, resembling pus.
The roar of the explosion was distorted, and the spreading flames no longer burned, but instead seemed to "rot," to "coagulate," turning into a caustic, viscous sludge that splattered across the sky.
In just a few breaths, the explosive energy that could have annihilated everything was forcibly transmuted and reshaped, controlled by Ku'gath into a slowly rotating "Plague-Cloud" covering the entire battlefield. Within the poisonous cloud, the shattered fragments of the exploded Plaguebearers writhed and merged, forming even more deformed monsters; the toxic flames had turned into a rain of corrupting spores, falling incessantly.