Nobody noticed the crystalline egg until it began to hum.
It started as a low, rising note, vibrating through the dark soil like a wet finger gliding along the rim of a crystal glass. Leah and Ainz, still sitting beneath the glowing canopy of the World Tree, heard the high-pitched harmonic resonance at the exact same fraction of a second. They turned together, their eyes locking onto the center of the stadium-sized clearing.
At the heart of the trampled grass, the Philosopher's Egg had begun to radiate a harsh, blinding luminescence. It had remained fractured ever since the initial spatial rift tore open. Now, thick streaks of unstable violet light poured outward from its fissures. The cracks widened with sickening speed, and from deep within the glowing shell came a horrifying sound—like a thousand metallic teeth grinding together inside a stone mortar.
"Blanc!" Leah shouted, springing to her feet and flaring her white wings. "Did you put anything else inside the egg after the skeletons?!"
"No!" Blanc yelled back, scrambling up from where she was resting with her multi-headed hound. "Just the thirty skeleton knights! Exactly like you told me!"
"And the Gate?" Lyla asked, her voice instantly dropping into a sharp, dangerous register as she stepped forward.
"The what?!" Blanc squawked.
"The Gate," Ainz said, his skeletal jaw clenching as he realized the horrific mechanical interaction. "My [Gate]. It is still open. In the confusion of our duel, I never cast the counter-command to close it."
Leah looked up at the spatial rift hanging in the night air—a jagged, frayed seam of pure white energy—and then down at the egg, where a thick, pulsing umbilical cord of dark purple mana was actively tethered between them.
"Oh, no," Leah breathed, her eyes widening in realization. "It's feeding."
"Feeding on what?!" Ainz demanded.
"On the Gate's raw spatial connection!" Leah explained frantically. "The egg's fusion algorithm is using the open link to siphon residual magic, lingering spells, and stray undead data from both worlds at once! It's trying to force-fuse everything within its magical reach!"
"Into what?!"
The Philosopher's Egg detonated.
With a deafening explosion that sent sharp, glowing crystalline shards showering across the grass, a towering monstrosity erupted into the sky. It was a horrifying amalgamation of pure skeletal architecture: thirty fused skeleton knights formed its dense lower core, reinforced by the heavy, spiked dark plate of a Death Knight, with the colossal ribs of an ancient dragon-like entity wrapping around its chest.
It stood fifty feet tall, sprouting a dozen thrashing, bone-armored limbs, with three giant skulls arranged in a rotating ring atop its shoulders. Its body continuously shifted, cracked, and reformed as it absorbed the floating ambient mana lingering from Ainz and Leah's prior spell clash. One of its central skulls snapped around to face the clearing, its cavernous eye sockets flaring with brilliant, blood-red fires.
"Great," Lyla deadpanned, raising a hand to shade her eyes. "The skeletal warlord grew up and hit its final evolution phase."
"An accidental cross-realm chimera," Demiurge murmured, his golden eyes glittering behind his glasses with what looked dangerously like professional admiration. "A perfect synthesis of undead structures from two separate world systems. Truly remarkable."
"Stop admiring the multi-world extinction threat and help us figure out how to destroy it!" Lyla snapped at him.
"My deepest apologies," Demiurge replied smoothly, taking a step back.
[Link] Sugaru: Boss! What are your orders?
[Link] Leah: Sugaru, issue an emergency ping to every megathairos in the sector! Bring the entire swarm here immediately! And command the local treants to form a defensive ring around the World Tree!
[Link] Sugaru: Executing immediately, Boss!
Leah turned back to the skeletal wizard standing beside her.
"Satoru," she said, her tone dropping into pure, calculated gamer-focus. "Can you take that thing out with a high-tier spell?"
"Not alone," Ainz answered, his internal combat analysis running at maximum speed. "If I cast a direct-damage attack spell at it, its active fusion core will likely absorb the ambient mana to regenerate or evolve further. Fusion-type entities actively feed on nearby casting."
"Then we don't give it any free mana to eat," Leah decided instantly. "We rely strictly on raw physical attacks, kinetic force, and our non-magical retainers. Can your Floor Guardians fight using pure physical pressure?"
Ainz turned to look at his Guardians. Without waiting for a command, they had already formed a disciplined, battle-ready vanguard across the field: Cocytus flexing his four massive arms, Shalltear spinning her blood-red spear, Aura drawing a heavy hunting bow with a pack of snarling magical beasts at her feet, Mare gripping his wooden staff with a determined expression, and Albedo standing out front, her black wings flared and her battle-halberd held in a lethal guard.
"I believe," Ainz said, a surge of pride swelling within him, "that they are more than capable."
Leah grinned, her dark energy blade flickering into her hand.
"Then let me show you how we raid in this world."
"Positions!" Leah shouted, her voice echoing across the stadium-wide field.
It was a raid-leader command she had given a hundred times before, and every single one of her allies moved instantly on instinct.
From the dark canopy of Trae Forest, a massive black cloud rose into the evening sky: a thousand megathairos—monstrous insects with the wings and heads of dobsonflies fused to the armor-plated bodies of centipedes—hummed like a roaring hurricane. They plunged from the sky in a blinding, glittering swarm, blanketing the chimera's upper limbs and tearing into its bone joints with razor-sharp mandibles.
Lyla raised her right hand toward the heavens. "[Abigor]!" she called out.
A massive dragon-like creature with shimmering blue scales swooped out of the clouds, firing a pressurized, high-velocity jet of water straight at the chimera's left arm. The pure kinetic force shattered the bone structure, sending giant jagged fragments spinning across the turf.
"Burgundy!" Blanc yelled, pointing wildly. "Bite its legs!"
All three of Burgundy's skull-heads lunged forward simultaneously, their massive jaws locking onto the chimera's main support leg with a sound like splintering oak. The central head, which had been fast asleep seconds prior, blinked its eye sockets, realized a boss fight was happening, and joined in out of sheer politeness.
"Charge!" Cocytus rumbled. The frost warrior sprinted forward on four legs, frost crackling along his chitin armor, and plunged his heavy claws straight through one of the chimera's three rotating skulls.
Shalltear darted around the monster's flank in a silver streak, her spear delivering a rapid-fire flurry of kinetic thrusts that carved deep gouges into its armored ribs. From the tree line, Aura loosed a salvo of heavy physical arrows, her hunting beasts harassing the creature's back ankles.
Mare, realizing he couldn't cast elemental earth magic without feeding the core, grabbed a massive, five-ton slab of broken bedrock with his bare dark-elf hands and hurled it like a pebble, slamming it directly into the chimera's midsection.
"I... I did not know I possessed such physical throwing power!" Mare gasped, staring at his small hands.
"Neither did I!" Aura yelled back in shock. "Mare! Watch out, behind you!"
"I see it, Aura!" Mare shouted, ducking as a stray bone limb swept overhead.
At the rear of the battle formation, Demiurge stood with his hands folded neatly behind his back, issuing calm, clipped strategic directives. "Left flank, execute a tactical withdrawal! Right flank, apply maximum physical pressure! Do not allow the target to turn its central sight line toward Lord Ainz!"
"It's heavily favoring its left side to compensate for the broken arm," Lyla analyzed, stepping beside him. "Draw its center of mass to the right."
"Understood," Demiurge nodded, adjusting his glasses. "Executing shift... Wait. It is adapting to our rotation pattern."
"Then we break protocol and alternate attack angles," Lyla countered instantly.
"Agreed."
They locked eyes for a brief fraction of a second, realizing they were reading the battlefield with identical tactical efficiency, before both turned away, slightly flustered to have found such a compatible strategic partner.
In the eye of the storm, Ainz and Leah stood shoulder-to-shoulder.
"This is an exceptionally complex mechanical problem," Ainz noted quietly.
"You're telling me," Leah replied, her eyes scanning the raid.
"As an arch-mage, nearly ninety-five percent of my arsenal relies on active mana casting. If I launch an offensive spell, I risk amplifying its mass."
"And my highest-damage sword skills all consume heavy MP," Leah said. "We're in the exact same boat."
They watched as Cocytus and Shalltear held the front line. But the chimera was constantly knitting its bone structure back together, and the physical stamina of the physical attackers was slowly beginning to drain.
"We have to strike its core," Leah determined. "Every single fusion-type entity in this game has a single anchor point where all the siphoned power converges."
"I can locate it," Ainz offered. "I possess a specialized non-offensive structural analysis spell. Because it deals zero damage and inflicts no status effects, it should pass under its absorption threshold. However, I will require absolute protection while I channel the scan."
"I'll be your tank," Leah said without hesitation. "What do we do once you ping the location?"
"I'll leave the physical strike to you," Leah grinned. "We're going to hit it with something that uses zero magic."
It was, by every metric, the most absurd crossover raid strategy ever conceived.
Ainz stepped to the center of the glade, spreading his dark-gloved arms wide. A pale, non-harmful blue grid of light expanded from his body, mapping the chimera's bone layout layer by layer.
Leah stood directly in front of him, spreading her white wings to form a physical meat-shield.
It was brutal work. The chimera's massive bone limbs smashed down toward Ainz again and again. Leah intercepted every strike, her [Dark Aegis] ringing like a struck anvil under the impacts. When the shield broke, her passive [Dark Carapace] absorbed the blunt force, causing her MP bar to take steady, heavy hits. Yet she didn't step back an inch. She had played main tank for a hundred raid groups, and she knew the golden rule: You swallow the damage, you hold the threat, and you protect your backline while they work.
"How's that scan coming?!" Leah yelled over the deafening roar of the battle.
"Almost finished!" Ainz shouted back, his skull glowing blue.
"Faster would be highly appreciated!"
"I am channeling as fast as the system allows!"
"Channel faster!"
Off to the side, Albedo was cleaving through three bone offshoots with her halberd, her black wings beating furiously. She stole a quick glance back toward the center of the field, where the Overlord and the human Queen stood side-by-side, holding the line together amidst the storm.
A strange, unfamiliar emotion flickered across Albedo's face. It wasn't the sharp jealousy she had felt earlier. It was... respect.
Lord Ainz has never looked like that in battle before, she realized inwardly. He isn't acting as a distant, lonely god—he's fighting as a partner.
She bared her teeth, whirled her halberd, and destroyed the remaining offshoots in a single, magnificent cleave.
"Target locked!" Ainz shouted.
The blue grid collapsed, focusing into a single, bright violet knot of concentrated energy pulsing deep inside the chimera's skeletal chest cavity.
"Blanc!" Leah screamed at the top of her lungs. "You're up! Take the shot!"
"On it!" Blanc yelled back.
She was already sprinting across the field, Burgundy thundering beside her as all three of his skull-heads roared in unison. She ducked under a sweeping bone arm, skidded through the grass beneath the chimera's legs, and pointed straight at the chest cavity.
"Burgundy!" Blanc cried. "Chomp the shiny purple spot!"
The middle head struck first, its massive skeletal jaws snapping shut on the violet core with the force of a hydraulic press. The left head clamped down a second later. The right head—the nap head—yawned sleepily, realized it was the grand climax, clamped down out of politeness, and crushed the core to dust.
The core shattered.
A blinding, silent wave of pure white light expanded outward, illuminating the entire forest in a brilliant flash. The fifty-foot chimera let out a final, echoing shriek. Its massive legs gave out, its glowing skulls flickered out one by one, and with a sound like a falling mountain of dry sticks, the entire monster collapsed into a harmless pile of gray ash.
An enormous, heavy silence settled over Trae Forest.
Blanc stood in the middle of the massive ash pile, blinking through the dust, while Burgundy's three heads drooped happily over her shoulders.
"…Did... did we win?" Blanc asked softly.
"You actually pulled it off," Lyla said, her voice filled with genuine shock.
"Burgundy did it!" Blanc cheered, hugging the hound's middle skull.
"Technically, the nap head did a solid thirty-three percent of the work," Lyla corrected with a faint smile.
"He really did!" Blanc said, tearfully proud.
Ainz lowered his glowing gauntlets, and Leah folded her exhausted wings. For a long time, the two leaders simply stood there side-by-side, catching their breath as they looked across the ash-covered battlefield at their battered, exhausted allies.
Then, Cocytus raised one massive four-fingered claw high into the air.
"For... the alliance," his deep voice rumbled across the clearing. "A magnificent victory."
"Hooray..." Aura cheered weakly, flopping onto the grass.
"Hooray..." Mare echoed softly, sitting down beside her.
The cheer cascaded through the crowd. Shalltear lowered her blood spear and let out a soft laugh. Demiurge removed his glasses, his hands trembling slightly as he polished them with his silk handkerchief. Sugaru, in her quiet, dignified manner, wiped a single tear from her compound eyes.
And off to the side, Albedo stood alone. She looked at Ainz and Leah, who were currently leaning against each other for mutual physical support, and slowly—reverently—inclined her head in a deep, formal bow.
It wasn't a bow meant for the Queen of Destruction, nor was it merely a ritualistic bow for the Overlord of Nazarick. It was a quiet, personal gesture that said: Thank you for showing us who you truly are underneath.
Ainz saw the gesture from across the field, though he said nothing.
But beneath his dark velvet robes, deep within the hollow, skeletal chest where a human heart used to beat, a soft, genuine warmth began to glow.