246: A sudden attack; the Zerg burrowed into the command center.

Seven days (KT-73 Star Field time) had passed since the first Zerg wave's impact.

During these seven days, the Zerg launched three more attacks of varying scales, each more cunning than the last. They began trying multi-point probes to find weak spots in the defense line; they would drive large numbers of Drones to forcibly fill certain trench sections under heavy fire to open paths for subsequent elite troops; they even tried using acidic slime secreted by the Creep to corrode depressions under the city walls, attempting to create closer detonation points for Banelings.

Under the "experience classes" of the veteran Leo and Lin Zhou's rapid adjustments, the Seventh Defense Sector successfully held off these attacks. Lin Zhou practiced the principle of "first wave heavy fire strike." When the Zerg vanguard was at its densest, he attempted for the first time to use the [Fire of Civilization] in the form of "Purifying Lotus · Scattered Petals" for large-scale, medium-intensity continuous burning. The effect was unexpectedly good—the physical destructive power of the Fire of Civilization against Zerg carapaces might not be as good as pure high-temperature flames, but its inherent "Order Purification" and "Conceptual Burn" characteristics caused additional "rule-level" damage to the Zerg biomass filled with chaotic evolution and devouring instincts. Zerg tainted by the Fire of Civilization not only had their flesh burned, but their movement coordination and attack desire also significantly decreased, as if some "underlying instruction" supporting their frenzied behavior had been interfered with.

This verified one of Lin Zhou's conjectures: high-dimensional conceptual powers like the Fire of Civilization might have a unique countering effect against a race like the Zerg, which seems mindless but actually relies on highly unified biological instincts and the Hive Mind. Of course, the consumption was also huge; a single "Scattered Petals" cost nearly 2,000 Divine Power points and could not be used frequently.

Zhao Hao and Wang Meng also grew rapidly. Zhao Hao's Dragon learned a more efficient "dive-raid-climb" cycle, specifically picking spots where Hydralisks and Banelings were dense to create maximum chaos with minimum consumption. Wang Meng's Behemoths and Dwarves integrated more closely with the wall fortifications, forming several solid "nails" specifically to deal with those Warrior Bugs lucky enough to climb the walls, even coordinating with Dwarf Thunder Crossbowmen to practice a "shield bash-crossbow shot" linked tactic for close-range enemies.

Over the seven days, Lin Zhou's Divine Power did not decrease through the cycle of combat, recovery, and more combat. Instead, due to high-intensity use and the stimulation of battlefield pressure, it showed faint signs of refinement and improvement. His subordinates underwent the tempering of blood and fire, their average Rank quietly increasing by 1-2 levels, and their combat coordination became increasingly seamless. The defense rating of the Seventh Defense Sector steadily ranked among the top in the internal base battle reports.

But the cruelty of war was far more than just frontal wall defense and offense.

On the evening of the seventh day (Astral Realm time), the two dark red suns in the sky slowly sank below the horizon, smearing the last traces of dim yellow light onto the scorched earth and damaged city walls. The scent permeating the air seemed a bit more complex than during the day; besides the usual smell of burning and sweet blood, there was an added hint of the sour rot unique to the night, coming from some biomass fermentation deep within the Creep.

The alert level remained at Level 2 (Yellow). Most combat units took the opportunity to rotate rest, eat, and maintain equipment. Lighting runes and searchlights on the city walls lit up one after another, illuminating the corpse-strewn plain outside in a deathly white, while casting long, flickering shadows inside the walls.

Lin Zhou was inside a reinforced bunker in the middle of the seventh wall section, with Zhao Hao, Wang Meng, and the veteran Leo, who had just come over to exchange experience. They were gathered around a simple sand table polished from Zerg carapaces, deducing possible new Zerg tactics. The sand table was marked with the base's peripheral defense layout and known active Creep zones.

"...So, the bugs' recent attacks have clearly been testing our fire blind spots and reaction speed." Leo pointed at several marked points on the sand table with a charred Zerg spine. "Here, here, and that rocky area in the northwest corner—their charge intensity and unit composition were all different. I suspect the damn Hive Mind is learning, collecting data, and planning something nasty."

"Learning?" Wang Meng scratched his head. "Those brainless bugs can learn too?"

"Whether the Hive Mind has a 'brain' is hard to say, but it definitely has similar functions." Leo exhaled a smoke ring. "It can receive information through the senses of every Zerg unit, analyzing our defense patterns, fire intensity, and reaction time. Then it adjusts its tactics. So, don't think everything is fine just because we held off a few times. The calmer it is, the more careful you need to be. You never know when it'll give you a 'surprise'."

Lin Zhou stared at the sand table, lost in thought. "If the Hive Mind is really analyzing our defensive weaknesses, then it might try to bypass our strongest frontal fire and launch an attack from somewhere we don't expect, or in a way we don't expect. For example..."

Before he could finish his sentence—

"BOOM!!!"

A muffled, extremely heavy sound, as if coming from deep underground, suddenly erupted from inside the base, near the central command area! Following that were more dense explosions, the roar of collapsing buildings, and a sudden, sharp, and urgent red maximum-level alarm, more intense than the previous Zerg wave alarms!

"Wooo—!!!"

The entire base's lighting System instantly switched to a piercing red warning state! Major General Rex's hoarse and furious roar came over the broadcast, with intense firefights and explosions in the background:

"Enemy attack! Inside the base! Underground! Zerg units have breached the underground defense layers! Coordinates: Sector B3, around the headquarters! All mobile units, assemble in Sector B3 immediately! Repeat, assemble in Sector B3 immediately! The headquarters is surrounded!"

Underground raid! Headquarters surrounded!

The faces of the four in the bunker changed drastically! No one expected the Zerg's "surprise" to come so suddenly and fatally! They had actually bypassed layers of ground defenses and directly raided the core of the base—the headquarters—from underground!

"Dammit! It's burrowing units! I should have known!" The veteran Leo crushed his cigarette butt, a fierce light exploding in his eyes. "The Zerg must have quietly dug tunnels during previous ground attacks, or used deep-drilling units we didn't know about! Quick! The headquarters cannot be lost!"

Sector B3 was the core command area of the base, where Major General Rex's headquarters, the main communication arrays, the energy hub, and some Senior officers and important logistical facilities were located! Once the headquarters was taken out, the entire base's command System would be paralyzed, and the defense System would immediately collapse!

"Lin Zhou! Zhao Hao! Wang Meng! Take your best fighters and most mobile people and follow me!" Leo almost roared, while the several Thunderfire Elementals around him, which had been in a semi-dormant state, suddenly shone brightly, emitting crackling electrical sounds. "Leave the walls to the deputies and automated defenses! Saving the headquarters is the first priority now!"

"Understood!" Lin Zhou didn't hesitate for a second, immediately issuing Orders through the mental link. "Elia, lead half of the Wenxin Elf Rangers and all the Priests to move with me! Grum, pick thirty of the most elite Tiangong Dwarf Warriors, carrying demolition tools and heavy weapons! The entire Lawful Merman Enforcement Squad, follow up! Zhao Hao, Wang Meng, bring your Dragons and half of your Behemoth and Dwarf elites! Move!"

The Orders were executed quickly. Within minutes, a rapid response force of about two hundred and fifty people, a mixed elite force from the three groups, assembled in the open space behind the Seventh Defense Sector. Leo also gathered his twenty Rock Giants and all eight Thunderfire Elementals.

"Go!" Leo led the way, his Rock Giants taking heavy strides and sprinting toward Sector B3 inside the base. Lin Zhou and the others followed closely.

The interior of the base was already in chaos. On the originally orderly corridors, soldiers, logistical personnel, and mobile units drawn from various defense zones were running everywhere. In the distance, toward Sector B3, flames soared, and the sounds of explosions, hissing, and shouting were incessant, with thick smoke billowing up.

The closer they got to Sector B3, the more tragic the scene became. Several main passages leading to the headquarters were blocked by violent explosions or collapsed buildings, and fierce fighting took place among the ruins. The attackers were a type of Zerg unit Lin Zhou had never seen in the illustrations!

Their appearance was somewhat similar to [Hydralisks], but their bodies were sturdier and lower, covered in thick, dark brown carapaces with a metallic luster. Their upper limbs had evolved exceptionally well; the ends were not bone-spine launchers but two pairs of huge, sickle-shaped bone blades that rotated like mining drills, along with a pair of relatively slender but sharp sub-limbs suitable for digging. They had no obvious heads; sensory organs seemed distributed throughout their torsos. Their movement was not crawling but a bizarre semi-upright way, utilizing rotating bone blades and forelimbs to alternately dig and propel themselves. They could move quickly on the ground, walls, and even ceilings, leaving behind neatly edged tunnel marks!

[New Zerg Unit (Provisional Name): Digging Piercer (Elite Variant)]

Sighting Rank: LV35-LV45 (Elite Template)

Sighting Quantity: Approximately 80-100 (scattered throughout Sector B3)

Morphological Characteristics: Sturdy and low, dark brown metallized carapace, well-developed upper limbs with rotating bone blades and digging sub-limbs.

Observed Abilities:

[Efficient Burrowing]: Can quickly dig tunnels in rock, alloy plates (non-specially reinforced), and foundation layers. Its bone blades carry high-frequency vibrations and a weak energy cutting field when rotating.

[Burrowing Thrust] (Core Threat): Can lurk underground or in the layers of walls and ceilings, suddenly bursting out of the ground/wall to launch high-speed piercing attacks with rotating bone blades, carrying armor-piercing and concussion effects. Raid distance: When lurking underground/in walls, it can thrust up to 15-20 meters!

[Carapace Reinforcement]: Extremely high physical defense, also has good resistance to energy attacks. Movement speed is average on the ground but extremely fast during digging and the moment of the raid.

[Swarm Coordination]: Seems to have simple tactical coordination, dividing labor for digging, luring enemies, and raiding.

Threat Assessment: Extremely High. Elite units specifically used for underground infiltration and vital point raids. Its Burrowing Thrust attack is highly sudden and high-damage, posing a fatal threat to fixed targets (such as headquarters, energy cores, communication arrays) and personnel who fail to react in time.

Currently, these "Digging Piercers" were using the complex architectural structure of Sector B3 and the underground network they might have quietly dug earlier to launch ghost-like attacks! Sometimes they would suddenly burst out of the ground, cutting a Sergeant Major who was organizing defenses along with his Rock Giant subordinates in half; sometimes they would erupt from the side walls, their rotating bone blades grinding a group of Elf Archers operating anti-aircraft guns into meat; some even drilled out from the outer walls or ceilings of the headquarters building, attempting to directly attack the command center!

The troops defending Sector B3 (mainly the Base Standing Guard and the personal guards of some officers) were caught off guard, suffering heavy casualties, and the defense line was cut to pieces. Major General Rex's voice constantly came from the direction of the headquarters, commanding the remaining troops in desperate resistance, but the situation sounded very critical.

"Spread out! Form combat teams! Watch your feet and the walls! These bastards will crawl out from anywhere!" The veteran Leo roared, taking the lead in commanding his Rock Giants and Thunderfire Elementals to charge. The Rock Giants, with their thick bodies and great strength, withstood the bone blade slashes of the Digging Piercers and smashed their carapaces with heavy stone fists. The Thunderfire Elementals released large areas of electric arcs and flames, interfering with their movement and burning their relatively fragile joint connections.

Lin Zhou also immediately commanded the troops to join the battle.

"Elia! Have the Priest Group expand their Purification Domain to its maximum range to disperse any possible Zerg pheromone interference and provide mental stability and injury suppression for all allies!"

"Wenxin Elf Rangers, take the high ground and fire at will! Focus your aim on the joints and sensory clusters of those Piercers that are digging or preparing to ambush!"

"Grum! Tiangong Dwarves, form a shield array and push forward! Use heavy weapons like war hammers and Explosive Tubes to deal with enemies that get close! Watch for vibrations beneath your feet!"

"Law Fishmen, disperse within the formation and enforce battlefield discipline! Focus on killing lone enemies attempting to ambush from the flanks or rear!"

"Zhao Hao! Get the dragons into the air, but don't dive recklessly! Use Dragon Breath to cover areas where Piercers are clustering, or perform precision strikes on targets posing the greatest threat to the headquarters building!"

"Wang Meng! Behemoths and Dwarves, follow Senior Leo's Rock Giants and form an assault spearhead to force a path to the headquarters! Cover each other and watch out for underground spikes!"

The instructions were clear and swift. After the tempering of the seven-day wall defense battle, this mixed unit displayed extremely high Execution efficiency. The arrows of the Literary Heart Elves accurately struck the digging points of the Piercers about to burst from the ground; although it was difficult to penetrate their thick carapaces directly, it disrupted their ambush rhythm. The Tiangong Dwarves' shield arrays and heavy weapons, coordinated with the Law Fishmen, Advanced steadily, clearing scattered Piercers along the way. Zhao Hao's dragons circled in the sky, seizing opportunities to unleash Dragon Breath, cracking the shells of clustered Piercers and sending them retreating with shrill cries.

But the greatest threat remained the unpredictable [Burrowing Spikes].

"Watch the ground on the left!" Lin Zhou suddenly warned sharply. Through his faint perception via the [Net of Law], he captured abnormal rule disturbances and weak vibrations beneath a seemingly flat patch of ground on the left.

No sooner had he spoken!

"Boom!"

The ground burst open! Amidst flying soil and rubble, two Digging Piercers shot out like cannonballs. Their rotating bone blades let out piercing shrieks as they stabbed fiercely toward the flank of the nearest Tiangong Dwarf shield array! Their speed far exceeded a normal Zerg charge!

"Shields up! Hold firm!" the Dwarf squad leader roared.

"Clang! Crack!"

The heavy alloy shields blocked the frontal thrust of the bone blades, but the massive impact and accompanying shockwaves still sent several Dwarf Warriors flying backward, spitting blood! A gap appeared in the shield array!

"Die!" A nearby Law Fishman Enforcer reacted instantly, his bone fork imbued with the Light of Order stabbing fiercely into an exposed gap in a Piercer's shell joints. The other was struck on its back carapace by Wang Meng, who had arrived just in time; sparks flew as his axe blow sent the creature staggering.

"The power and speed of these damn things' spikes are insane!" Wang Meng shook his numbed arm, still feeling a lingering fear. If the Dwarf shield array had been any thinner or their reaction a split second slower, it wouldn't have been as simple as just being shaken and injured.

The battle was exceptionally brutal. A price was paid for every step forward. Piercers constantly burrowed out from unexpected places, causing casualties. Although Lin Zhou's troops were elite, they still seemed somewhat ill-adapted to facing these elite units specifically designed for ambush and infiltration. The Literary Heart Elves' arrows struggled to inflict fatal wounds, the Tiangong Dwarves' heavy weapons required close quarters, and the Law Fishmen were better at dealing with intelligent beings who could be judged for "crimes," showing average effectiveness against these pure killing machines. Only Zhao Hao's Dragon Breath and Leo's area-of-effect lightning and fire elemental attacks were more effective, but the enemies were scattered and adept at using cover.

"We can't keep grinding like this! The headquarters won't last long!" The veteran Leo's eyes were bloodshot; one of his Rock Giants had just been simultaneously ambushed from underground by three Piercers and forcibly torn into rubble. "Lin Zhou! You academy types have plenty of ideas! Is there any way to quickly clear out these burrowing rats, or at least find their underground tunnel network?"

Lin Zhou's mind raced. Conventional methods were too inefficient... Burrowing ambushes... Underground networks... "Li Mo!" He immediately called out via a remote mental link (which suffered significant interference inside the base but was barely usable over short distances) to the Master of the Research Hall back at Xinghai University. "Emergency! We've encountered a new type of Zerg burrowing elite unit capable of rapid digging and Burrowing Spikes with heavy carapaces! Any specific mechanical or detection solutions? As fast as possible!"

A few seconds later, Li Mo's urgent voice came through, carrying the hoarseness of staying up late for research and the excitement of encountering a new subject: "Burrowing units? High-frequency vibration digging? Give me a simple topographic map of your combat zone and the enemies' physical characteristics! Quick!"

Lin Zhou immediately transmitted the general terrain (via Divine Thought scanning) and images of the Digging Piercers.

About another minute passed, filled with the sound of frantic blueprint flipping and calculator tapping on Li Mo's end.

"Got it! Try this! A temporary solution!" Li Mo transmitted a flow of information. "The setup for a [Simple Ground Vibration Sensing Array (Overclocked Edition)]! Use your existing rune substrates—the Dwarves should have brought spares—and a few energy cores to quickly set up a temporary array that can amplify and identify weak underground vibrations! It can roughly map out the movement tracks and possible lurking spots of the underground bugs! The precision isn't high and the range is limited, but it should be enough for early warning!"

"Also, targeting their heavy carapaces and melee nature, you can try using [High-Frequency Oscillating Armor-Piercing Mines]—modify your existing Explosive Tube runes. I'll tell you how. Make the shockwave from the explosion release in a specific high-frequency oscillating form; it works wonders against rigid carapaces! But they need to be thrown at close range or set as tripwire traps!"

The information flow included specific rune arrangements, energy circuit connection methods, and simple modification diagrams for the Explosive Tubes.

"Grum!" Lin Zhou immediately shared the information with the Tiangong Dwarf Great Master. "Take your engineers and start setting up the 'Vibration Sensing Array' immediately! Prioritize covering the area ahead of us leading to the headquarters! Everyone else, provide cover!"

"Leave the Explosive Tube modifications to my men!" Wang Meng roared; his Dwarves also had knowledge of explosives.

"Zhao Hao, have the dragons use Dragon Breath to clear a relatively safe area to make it easier for Grum and the others to set up!"

At this life-or-death moment, everyone exploded with incredible efficiency. Under the cover of Dragon Breath, Rock Giants, and Behemoths, Grum led several Dwarf runemasters, dodging spikes that occasionally burst from the ground or walls, as they scrambled through the scorched earth and ruins. Following the diagrams provided by Li Mo, they quickly buried metal plates engraved with specific runes and connected them with energy lines.

Meanwhile, Wang Meng's Dwarf Warriors took the dozen or so standard Explosive Tubes they carried and urgently adjusted their internal rune structures and charge ratios according to Li Mo's modification method.

This process lasted about five minutes, yet it felt as long as a century. Three more Tiangong Dwarves and one Law Fishman lost their lives to sudden Burrowing Spikes while providing cover for the setup.

Finally!

"Array activated!" Grum shouted as he inserted the final Mid-Grade Spirit Stone into the core node, activating the runes!

"Buzz—!"

A pale yellow halo, like a ripple on water, quickly spread out from the array's core, covering an area of about a hundred by a hundred meters ahead. Wherever the halo passed, the ground seemed to turn into semi-transparent amber, within which several rapidly moving, distorted red lines faintly appeared! Those represented the abnormal underground vibration sources—the movement tracks of the Digging Piercers! There were even relatively static but bright red dots appearing beneath several building ruins—those were units lying in wait for an ambush!

"I see them! Eleven o'clock direction, twenty meters underground, two red dots are closing in fast!"

"There are three stationary red dots under that pile of rubble directly ahead!"

"At the base of the right wall, there's a movement track passing through the wall!"

Grum and several Dwarf engineers shouted out the positions.

With this warning, the situation changed!

"Literary Heart Elves, fire a volley at the marked ground! Disrupt them!"

"Zhao Hao! Dragon Breath, cover that rubble pile with the three red dots!"

"Wang Meng! Behemoths, go to the eleven o'clock direction and smash them as soon as they show their heads!"

"Senior Leo, have your lightning and fire elementals use area-of-effect arcs to cover that wall-crossing track area!"

Lin Zhou's command became more precise and targeted than ever before. Knowing the enemy's position and movements in advance, even if only roughly, was enough for the defenders to shift from being passive targets to active interceptors!

"Boom, boom, boom!" The Dragon Breath blew the rubble apart, forcing the three lurking Piercers out early. Their carapaces were scorched black and their movements staggered; they were immediately riddled with holes by concentrated fire.

"Roar!" The Behemoths roared, their massive claws slamming down on the two Piercers that had just burst from the ground at the eleven o'clock direction, forcibly smashing them back into the pit!

The lightning and fire elementals' arcs covered a section of the wall. Although they didn't kill the Piercers behind the wall directly, the intense electrical interference clearly caused them great agony, making their movement tracks become chaotic.

"Now! Throw the modified Explosive Tubes onto the ground near those bright red dots! Set them for delay or tripwires!" Lin Zhou roared.

Several agile Dwarf Warriors, under the cover of Wang Meng's Behemoths, rushed toward several marked lurking spots, threw the modified [High-Frequency Oscillating Armor-Piercing Mines] with all their might or set up tripwires, and then quickly retreated.

"Bang! Bang! Bang!"

Dull thuds, slightly different from ordinary explosions, rang out. The fire from the explosions wasn't dazzling, but the resulting shockwaves carried a tooth-gritting high-frequency oscillation. The targeted ground and walls suddenly caved in and cracked as if repeatedly struck from within by invisible heavy hammers! Even if the lurking Digging Piercers weren't killed outright, their thick carapaces developed massive cracks and structural failures under this targeted oscillatory impact. Their mobility was severely compromised, or their shells shattered completely, exposing the fragile tissues inside!

"It's working!" Wang Meng roared excitedly.

With the early warning from the Vibration Sensing Array and the targeted lethality of the High-Frequency Oscillating Armor-Piercing Mines, their advance speed increased significantly. The remaining Digging Piercers seemed to sense the threat and began attempting to retreat or dive into deeper layers of the earth.

"Don't let them escape! Chase them down! Clear the path to the headquarters!" The veteran Leo, eyes bloodshot with battle lust, commanded the Rock Giants to charge forward.

Lin Zhou also led his troops in close pursuit. His gaze was already locked onto the main headquarters building ahead, which flickered in and out of view amidst the fire and thick smoke, with occasional explosions and roars echoing from within.

This sudden underground ambush had forcibly dragged their team, which was originally just "interns," into the core battle zone that would determine the survival of the entire base.

And the test was only just beginning. The situation inside the headquarters was likely even more critical than outside. They had to break through as quickly as possible to rendezvous with Major General Rex to stabilize their position and wait for reinforcements from other defense sectors.

The cunning and lethality of the Zerg were displayed to the fullest at this moment.