I summoned the Fourth Scourge in Warhammer

Chapter 247 Sustainability: Draining the Pond to Harvest
To Regan's surprise, once they received his official orders, the suicide squad acted with astonishing efficiency.

One moment they were arguing over trivial matters, the next they seemed to have transformed into model soldiers from the Imperial military textbook. The communications officer's orders were clearly transmitted to every squad, and the roar of engines echoed throughout the camp.

Before long, several Hellhound flamethrower tanks were the first to drive out of the camp, their tracks grinding heavily across the barren ground. Close behind them were squads of infantrymen armed with flamethrowers, marching with swift steps, their previous laziness completely gone.

Regan sat in a Chimera armored personnel carrier and followed the troops to the target area.

Although the main force has wiped out the large Tyranid creatures, the alien ecosystem still stubbornly occupies this land.

The plants that once belonged to Plantim had long been devoured and assimilated, replaced by a bizarre and grotesque jungle. Huge, fungus-like "trees" rose from the ground, their canopies covered with pulsating, vein-like patterns; on the ground, twisted vines coiled and coiled like purple pythons, bearing fleshy flowers that opened and closed as if breathing; and there were also translucent vesicle plants that swayed gently in the breeze, with an unknown liquid seemingly flowing inside.

The place was undeniably disgusting, and Regan frowned at the sight. He couldn't wait to give the order to destroy it.

"Fire!"

As soon as the order was given, the hellhounds' heavy flamethrowers unleashed their power, the orange-red solidified fuel, like the breath of an angry dragon, instantly covering a large area in front. Immediately afterward, the infantry also pulled the triggers, tongues of fire licking every corner of the fungal carpet and penetrating into the plants.

Flames soared, billowing black smoke tinged the sky with an ominous gray-black hue. The tenacious Tyrannosaurus organisms crackled and popped under the intense heat, their translucent vesicles expanding and bursting in the flames, spewing out boiling fluids. The fungal carpet curled and charred, sizzling and burning, filling the air with an indescribable acrid stench of protein mixed with chemical fuels.

Regan peered through the chimera's observation window at the scene before him. Flames devoured all traces of the aliens, turning the polluted land back into scorched earth. A pure sense of satisfaction rose within him—this was in line with his preconceived notions of human armies, this was the proper posture of the Empire: the most thorough and ruthless cleansing of all alien filth.

However, after the initial exhilaration, Regan quickly realized something was amiss, and his brows began to furrow.

He was also a person with formal military education, and had some knowledge of biology and engineering. It's basic common sense that plant roots extend deep into the ground to absorb nutrients. If ordinary plants do this, then wouldn't the "roots" of a highly aggressive, collectively-minded alien species like the Tyrannosaurus extend deep into the earth's crust?
Simply burning the surface layer of the ground like this is merely "cutting away the weeds," and doesn't address the root cause. Once the fire goes out, these things will regrow from the ground in no time. This is just treating the symptoms, not the underlying problem, and is a pointless waste of fuel.

With this question in mind, Regan contacted Tang Ren and his two teammates in the command vehicle directly via communicator. "Commander Tang Ren, I have a question," Regan's voice came through the electrical connection, "Can burning the surface like this really completely eliminate the Tyranid biomass? Won't their roots have already penetrated deep underground?"

Tang Ren's relaxed laughter came from the other end of the communicator: "Political Commissar, don't worry. Tyran won't take root too deep, otherwise it will absorb too much nutrition from the depths of the earth. Don't be fooled by the fact that Plantim looks like a dead world now. In a few hundred or a few thousand years, as these toxic gases and radiation dissipate, the native creatures lurking deep underground will gradually rise up and make this planet vibrant again."

Regan was stunned and couldn't understand what he was saying for a moment. According to this logic, with Tyrannosaurus's determination to devour the planet, shouldn't he be more determined to extend his roots deep into the ground and squeeze out all the biomass on the planet?

Tang Ren's voice continued, in an tone that seemed to be explaining the game's background setting: "By then, the Tyranid hive fleet, which has already gone far away, will be able to return around the same time, and we can have another round of feasting, right? A few thousand years is just a blink of an eye for hive creatures like the Tyranids. They also understand 'sustainability and exhausting resources.' So, the Tyranids don't even bother to actively seek out creatures deep underground, let alone eat them."

Tang Ren's words are also verified in the original work. For example, the Alien Inquisitor Koptman discovered the legacy buried deep underground by the Motor Workers on Tyran, and found information about the Cult of Mechanics, thus confirming the existence of the terrifying Tyrannosaurus.

After hearing this explanation, Regan fell into a long silence.

This theory... sounds utterly absurd, yet it carries a chilling cruelty, treating a planet as a farm that can be harvested repeatedly? The more Regan thought about it, the less it seemed out of place; it actually fit the image of the Tyranids.

Moreover, he was, after all, a political commissar fresh out of academy, and his understanding of Tyrannosaurus came entirely from intelligence gathering gathered before his arrival. These suicide squad members, however, were veterans who had genuinely fought Tyrannosaurus on Plantim for years. No matter what, he couldn't possibly understand Tyrannosaurus as well as they did. Perhaps the theories he had just mentioned already represented a consensus among the suicide squad members regarding Tyrannosaurus's habits.

Having thought this through, Regan didn't ask any more questions, tacitly accepting Tang Ren's explanation.

But he was, of course, unaware that the "setting" Tang Ren casually mentioned was known to very few within the entire Empire. Although the Technologists of the Cult of Machines on Mars had also discovered, through analyzing battlefield data, the strange phenomenon that Tyrande seemed to intentionally avoid the planet's deep biological matter, this was, after all, the Empire's first large-scale war with Tyrande, and everything was still in the exploratory stage. For the Technologists, this was merely an anomaly requiring more data to corroborate its findings.

This isolated case is insufficient to prove anything, and no one can be certain that this is Tyranids' inherent behavioral pattern, let alone deduce such a grand and terrifying strategic policy from it. This sinister wisdom, which views the entire planet as a cyclical farm, has already exceeded humanity's current conventional understanding of the Tyranid threat.

(End of this chapter)