Reborn in the Apocalypse :The son In-law's revenge

Chapter 14:The Apex Vault

The massive steel doors slammed shut behind them, sealing with a deafening CLANG that echoed through the frozen hallway.

[System Alert: Dungeon Rules – No Exit. Kill the Boss to leave. Environmental Hazard: Absolute Zero. HP will drain by 1% every minute.]

Leo cursed under his breath. The temperature in the vault was already below freezing. His breath plumed in the air, and a thin layer of frost was forming on his Apex Carapace armor.

"A timed death trap," Mia said, her pale eyes scanning the dark corridor. "The Architects really don't want anyone finding their secrets."

"Then we move fast," Leo said. He drew the Hive Reaper. "Stay close."

They pushed through the facility. The architecture was a sterile, white labyrinth of reinforced glass and steel. But the deeper they went, the more grotesque the environment became. The white walls were replaced by pulsating, organic metal veins.

They passed a row of stasis tanks. Inside were failed experiments—twisted, humanoid abominations floating in green fluid.

Mia stopped. Her breath hitched.

[System Alert: Hidden Subplot Unlocked – The Lost Subjects of Project Apex.]

"I remember this place," Mia whispered, her voice trembling with a rare display of fear. "Sector 4. This is where they kept the failures. The ones who couldn't handle the Apex System."

Leo looked at the tanks. On the glass of one tank was a faded number: Subject 00.

"You were the first," Leo said quietly. "The prototype."

"I was the only one who survived the initial bonding," Mia said, her hands clenching her daggers. "When the system activated and the apocalypse began, I broke out. I left them all behind in this frozen hell."

"Then let's make sure we don't join them," Leo said, placing a firm hand on her shoulder. "Focus on the mission. We kill the boss, and we blow this place wide open."

Mia took a deep breath, her cold mask sliding back into place. "Right. Let's hunt."

---

They reached the central chamber. It was a massive, domed arena. In the center sat a towering, six-legged mechanical monstrosity. It was an Apex Sentinel, a prototype weapon designed specifically to kill high-level system users.

[System Alert: Tier 5 Dungeon Boss – Apex Sentinel 'Titan'. Level 34. Recommended Party: 5. You have: 2.]

The Titan's red optical sensors flared to life. It let out a mechanical roar, and two massive plasma cannons emerged from its shoulders.

"Scatter!" Leo shouted.

They dove in opposite directions as twin beams of superheated plasma vaporized the spot where they had just been standing.

Mia vanished into the shadows, reappearing on the Titan's back. She drove her daggers into its joints, trying to sever the cables. The Titan bucked violently, slamming its massive body into the wall. Mia was thrown off, crashing into the ground with a sickening crunch.

[Mia HP: 30/180. Status: Critical.]

"Lily!" Leo shouted into the comms, but only static answered. They were too deep underground.

The Titan turned its attention to Leo. It raised a massive mechanical fist and brought it down. Leo dodged, but the shockwave shattered the floor, sending him flying backward.

[Critical Hit! HP: 140/300.]

Leo pushed himself up, spitting blood. The Titan was too heavily armored. His glaive would barely scratch it.

He needed something stronger.

He opened his inventory. He had three Tier 4 items he had been saving: a broken Harbinger wing, a chunk of the Hive Queen's carapace, and a high-density energy cell from the Harbinger's core.

[Synthesize: 3x Tier 4 Items → 1x Tier 5 Item?]

[Warning: Synthesizing will consume all three items.]

[Confirm? Y/N]

Leo pressed Y.

The three items dissolved into brilliant light, swirling together in his hands. The light condensed, forging a new weapon.

[Synthesize Successful!]

[Obtained: Tier 5 Weapon – Apex Breaker (Greatsword). Effect: +60 Strength. 50% Armor Penetration. Skill Granted: Graviton Slam.]

Leo gripped the massive, dark-metal greatsword. It hummed with a terrifying, crushing gravity.

The Titan charged, its plasma cannons glowing for another blast.

Leo activated his new skill: [Graviton Slam].

He leaped high into the air, bringing the greatsword down. A shockwave of dense gravity exploded outward, pinning the Titan to the floor. The mechanical beast groaned under the sudden, crushing weight.

Leo landed on the Titan's head and drove the Apex Breaker straight through its central processor.

The Titan shuddered. The red light in its eyes died.

[Devour Successful. +40 Strength, +30 Vitality, +30 Agility.]

[Level Up! You are now Level 30.]

[Level Up! You are now Level 31.]

The dungeon's environmental hazard shut off. Warm air hissed from the vents.

Leo fell to his knees, gasping. He had done it. He had broken through to Level 31.

He limped over to Mia. She was unconscious, her breathing shallow. Leo quickly pulled out the Trophy 3—a Tier 5 Medical Stim he had looted from the Titan's carcass—and injected it into her neck.

Mia gasped, her eyes flying open. The wounds on her body began to close.

"Did we win?" she rasped.

"Yeah," Leo said, helping her up. "We won."

He walked over to the Titan's corpse. A hidden compartment had opened in its chest, revealing a glowing data chip and a strange, dark key.

[Item Acquired: Citadel Protocols Data Chip.]

[Item Acquired: Vault Master Key.]

[Trophy 1: Immediate Use – Apex Breaker Greatsword (Level 31 reached).]

[Trophy 2: Future Plot – Citadel Protocols Data Chip (Contains the layout of the Architects' fortress).]

[Trophy 3: Give Away – Vault Master Key (Leo would give this to Elara to unlock the rest of the vault's resources).]

"Let's get out of here," Leo said. "I need to check on the base."

They rushed back to the entrance. The doors hissed open, and they stepped out into the parking garage.

But something was wrong.

It was too quiet. There were no guards. No noise from the mall above.

Leo's comms suddenly crackled to life. Natasha's voice was frantic, barely a whisper.

"Leo... don't come up here. It's a trap."

"Natasha?" Leo said, his grip tightening on the Apex Breaker. "What's happening?"

A new voice echoed through the comms. Arrogant. Smooth.

"Welcome back, Son-in-Law," Lucian said. "I've been waiting for you. I have your little Vanguard here. And your base is surrounded by a horde of mutated monsters. Come up, and let's have a chat."

The line went dead.

[System Alert: Base under siege. Hostage: Natasha Volkov. Threat: SSS-Class 'Lucian' and a Mutated Horde.]

Leo's eyes went cold. The Apex Breaker pulsed with dark gravity in his hand.

"Mia," Leo said, his voice devoid of emotion. "We're going hunting."