Location: Barbarus, Northern Mountains, the domain of the Xenos Lord Necare, the path to the peak.
Now.
Upwards, always upwards.
The toxic mists grew thicker with every step. Each stride upwards felt like the poison was gnawing at their armor.
Visible to the naked eye, the anti-corrosion layer on the armor flaked away, revealing the shining metal beneath.
Yet, as soon as the metal was exposed, rust began to spread and crawl over it.
Some of the Death Guard, due to previous battles, had deep gashes in their armor. Through these gashes, one could now clearly see the innermost layer of padding. A black and yellow hue spread over the fabric, which now seemed as fragile as paper, ready to tear at the slightest touch.
They were now nearing the peak. Since the last artillery barrage, Mortarion and his retinue hadn't encountered much resistance. Occasionally, a few high-ranking puppets would attempt ambushes using the terrain, but Mortarion dispatched them in moments.
It seemed that the Xenos Lord Necare, cut off from supplies and surrounded, was nearing his end.
However, more than the enemy, the inherent toxicity of Barbarus seemed to be the greater challenge for the group.
Hazniel was the first to falter.
The poison seeped through a large gash in his leg. It was horrifying to see the skin on his leg begin to peel away, revealing corroded, whitened muscle beneath.
His labored breathing echoed from within his armor, clearly suppressing his pain.
Mortarion spoke, "Mulnau, take Hazniel and retreat down the mountain. Regroup with Mozar."
Mulnau looked up at Mortarion. Hades felt that Mulnau wanted to say something, but his own sluggish movements betrayed his condition.
"Understood."
Supporting the weakened Hazniel, who was clearly unwilling but incapacitated by the poison, the two began their descent.
Yet, as they ascended further, the poison only intensified.
Karlastifon struggled to breathe. His respirator was at maximum capacity, its buzzing indicating it might fail at any moment.
He checked his weapon and noticed a clear fracture where the handle met the body.
Breathing tubes began to melt and fall within the layers of his armor.
The remaining Death Guard were also at their limits.
Their movements grew slower, their breathing more labored. Beneath their armor, their faces were likely pale, yet they persisted.
"Karlastifon, lead the remaining Death Guard and retreat," Mortarion's voice, filled with restraint and suppression, echoed.
Even in the finest armor, even as a Primarch, the poison here was not to be underestimated.
Karlastifon knew they were at their limits. Any further, and they'd be crossing a point of no return.
But could Mortarion truly defeat the Xenos Lord Necare and escape?
"Mortarion, do you intend to continue the ascent?"
"Yes."
Mortarion gritted his teeth. He had to personally end his father. He had come this far.
His father was openly mocking him. In the areas with the densest poison, there were no defenses—
He was mocking Mortarion's reluctance to ascend further, mocking the idea that Mortarion could ever defeat him.
The die was cast.
Today, between Necare and him, only one would survive.
Karlastifon felt something move past him, heading towards Mortarion.
He paused. Was it Hades?
"Hades, are you also continuing the ascent with Mortarion?"
"Yes."
Hades was not faring well either. Even though both his and Mortarion's armor had a second layer sewn from the Xenos Lord's hide, he could feel it slowly melting under the poison's assault.
Time was running out.
Not to mention, Hades's armor lacked a respiratory system, making his breathing even more challenging.
But Hades could still endure.
He wasn't at his breaking point yet.
He could still ascend.
Karlastifon shook his head as if hearing something unbelievable, but he said nothing. Leading the remaining Death Guard, he began the descent.
Before leaving, he took one last look at Hades and Mortarion, as if to etch their figures into his memory, or perhaps mourning them in advance.
Mortarion's towering figure slowly disappeared into the mist, and with him, a suffocating aura.
The peak was in sight.
The two silent climbers continued upwards.
"Can you manage?" Mortarion's voice echoed again, "We need to end this quickly."
Hades responded with a bitter smile.
Clearly, even with the Xenos Lord's hide sewn into their armor, the full enclosure couldn't function long in this toxic environment.
Once the armor failed, even as a Primarch, one couldn't maintain consciousness in such conditions.
"Just as I thought," Mortarion glanced back at Hades. If Hades could help weaken his foster father's psychic powers, Mortarion was confident he could deliver the killing blow.
"Also, thank you."
Hades paused, "It's nothing. I know how it feels to fight alone."
Hades had once fought alone in the south.
In many critical moments, having an ally would have made things much easier.
He hoped he could suppress Lord Necare's psychic powers.
The peak was reached.
It was a flat area, roughly the size of a basketball court, as if a chunk of the mountain had been cleaved off.
A tall, eerie figure stood there, surrounded by the toxic mists. A tattered cloak draped over its shoulders, fluttering without wind.
In truth, Mortarion's foster father, Necare, looked more humanoid than most Xenos, albeit much taller and bulkier, like a giant.
He wore a simple combat attire, adorned with intricate ritualistic drawings and runes.
His pale, grayish skin was exposed directly to the poison, showing no signs of corrosion, as if he was born from the mists.
His eyes, deep-set, were surrounded by pale, yellow-red veins.
Ominous green-black psychic energy crackled around him.
In his pale, massive hand, he held a scythe named "Annihilation", its hue a strange copper-purple due to alien technology.
Necare didn't wait in his lower-altitude fortress but stood alone at the peak.
Upon seeing Mortarion, he let out a derisive chuckle.
"You've finally come, my weak son."
In a flash, Mortarion, scythe in hand, charged.