The battle in the material universe is over. But what about the Rainfather? - After being defeated by Mortarion and crashing to the ground, empowered by the WAAAGH!! energy, Mortarion thoroughly humiliated the Rainfather. In the end, the disgraced Father Yufu chose to self-destruct.
Of course, the above is pure fiction.
The truth is, when the Rainfather Rotigus realized that only his loving father Nurgle could retrieve Ku'gath, he decisively self-destructed. Because whether Nix succeeded or failed, the next wave of rage would be directed at him. Rather than be killed by Nix, it was better to take his own leave.
Among the many daemons of Nurgle, Rotigus was wise enough, and he lacked Ku'gath's habit of working hard before fleeing, so he simply retreated into the Empyrean.
But Ku'gath's end was far more miserable—he was completely erased on the spot, and even his loving father Nurgle permanently lost a finger. This scar could not be healed, and Ku'gath himself carried a portion of Nurgle's divinity; his demise meant Nurgle had forever lost that power, and birthing a new Ku'gath would take a long time and a great deal of energy.
But Nurgle still waits. The fiasco in the material universe is not the end, and his counter-stroke has yet to be revealed. He stares at Typhon, who still sleeps, confident that Nix is unaware of his arrangement. He knows Typhon received a warning from Nix at that moment, but it doesn't matter—it was merely an echo of Nix's residual power; the real Nix does not know what transpires in the depths of Typhon's soul.
At this time, Typhon stands at the most important crossroads of his life.
He sees a vision of the future: they ride together aboard the Terminus Est. In the corridors are familiar figures, as well as many warriors he has never seen before.
It should have been an ordinary warp journey, until they became trapped in the Empyrean. Gradually, fear began to seep in.
The plague did not strike directly as it did on Barbarus, but grew secretly, like a living thing. Visions and whispers gradually appeared in everyone's mind.
The air circulation system failed first, and a sweet, greasy stench of rotten overripe fruit, mixed with filth and an unfathomable breath, penetrated every centimeter of the ship's space. The bulkheads began to 'sweat', and instead of water droplets, it was a glistening, strangely colored slime that slowly dripped down, leaving obscene lines on the deck.
Pipes groaned, no longer carrying clean water and air, but warm pus and churning spore clouds. This was not an alien invasion, but the vast ship itself, saturated with Empyrean evil, coming alive from within and beginning to rot.
The warriors were not attacked by daemons, but were themselves decaying. Typhon saw the grim, sturdy men from Barbarus he knew, and warriors from Terra he did not, all suffering in pain.
At first, they resisted fiercely, cauterizing diseased limbs with hot melts, cutting away flesh attached to armor, locking the howling infected in isolation chambers. Mortarion himself stood on the bridge, like an obstinate rock in a storm, his respirator mask gulping desperately, trying to filter the omnipresent corruption, but the edges of the mask began to rust, and the filter tank emitted an ominous, wet hiss.
Every purification brought a more violent counterattack, and every treatment spawned more stubborn afflictions. Despair came not from a powerful enemy, but from the betrayal of life itself—their cells joyfully embraced death, nerves twisted intense pain into signals of approaching bliss. The will to resist, in this slow, endless, and incomparably 'loving' consumption, softened and peeled away like soaked skin.
The Primarch's submission was not born of anger. Mortarion could no longer bear to watch his sons continue to suffer.
The vision focused on that decisive moment: Mortarion looked around at his Legion. Instead of the brave and fearless warriors of the Death Guard, he saw bodies slowly dissolving in their own juices, diseased yet pitifully unable to die.
He used his rationality to fight the Empyrean, his hatred for psychic powers, and his iron will—all became a mockery in the face of this 'natural process' that transcended the laws of physics.
His pride, the pride that made him survive the gas of Barbarus, kneel before the throne of Terra, and ultimately betray him, was washed away by this all-consuming tide of decay.
He did not erupt in rage or ecstasy, but bowed his head in a deeper, more terrifying realization: he could not save them unless he accepted this 'salvation'. What he sent to the Plague Lord was not a plea, but a roar of surrender. At that moment, the heart of the Terminus Est beat violently, like a birthing pang, and all the pain miraculously ceased, transforming into a numbing corruption.
The birth of 'Typhus'—the perfect embodiment and final description of this process.
In the vision, the one who was once Typhon experienced the suffering of all the warriors and was chosen to bear an even greater burden.
His transformation clearly demonstrated the essence of Nurgle's 'grace': the fusion of flesh with ceramite and steel was not a punishment, but an immortal form of giving; rot and pus were not defects, but proof that life overflows; unending pain was not torture, but the self-inflicted, continuous caress of the loving father.
When he—when Typhus—finally staggered towards his Primarch, he was no longer a man, nor even any kind of daemon. He embodied a concept: tolerance towards the doomed, the abundance of death, and the ultimate denial and acceptance of all struggle. Every pustule on his bloated body silently preached; every groan in his guttural voice repeated a single truth: all is corrupted, and all beings are immortal.
The illusion faded, leaving Typhon not with fear, but with a cold, stagnant sense of emptiness. Nurgle's 'counter-stroke' was presented at this very moment: it was not direct violence, nor temptation, but the ultimate fusion of all possibilities into a fact, like a malignant seed sown into his soul.
The choice lay before him: burn everything he had to fight this 'love' that encompassed its own end, or accept the predestined, moist tranquility in advance, as the illusion showed? Nix's warning still echoed in his ears, and he stood here alone; only he could make the choice.
Typhon did not know whether he should merge with this fate—it would mean fully accepting everything that 'he himself' had done. His pride as a Liberator roared in refusal, and deep within, he still instinctively resisted. This contradictory rift became a silent war within itself.