The symbiote dragon, Grendel, was officially the most terrifying, insurmountable threat the Avengers had ever faced.
Even during the Battle of New York, the Chitauri army had been flesh and blood. They could be punched, shot, and blown up. But against a fifty-meter monster made entirely of primordial, impact-absorbing space-sludge, physical attacks were virtually useless. Every punch thrown by the ground team was merely a distraction. The only combatants inflicting any actual damage were the Human Torch and Jack of Hearts, and even their concentrated thermal and energy blasts were barely leaving a dent in the dragon's rapidly regenerating hide.
High above the street, Grendel unhinged its massive jaws and unleashed a torrent of pitch-black, living flames.
The dark fire slammed squarely into Goliath. The sixty-foot-tall hero grunted in agony, stumbling backward and crashing heavily into the glass facade of a high-rise office building.
Down on the street, Captain America dodged falling debris. He threw his vibranium shield, decapitating a leaping symbiote minion, and caught it flawlessly on the rebound. He was grounded, completely incapable of fighting a flying dragon. His only job was to hold the line at the front doors of Avengers Tower, keeping the endless swarm of foot soldiers from breaching the civilian shelter.
To ensure the high-frequency acoustics didn't incapacitate the heroes, Steve had ordered the perimeter sonic-cannons powered down. Only the airborne Ultron sentries were cleared to use sonic weaponry, swooping down to blast any alien that crossed the barricade.
Steve didn't want to be relegated to crowd control. But he knew the tactical reality: as long as Captain America was standing in front of those doors, the people inside would not give up hope.
Steve tapped his earpiece, ducking under a wildly swinging black tendril. "Tony! Tell me the brain-trust has a solution!"
Miles away, safely secured inside the Baxter Building, Tony Stark let out a deeply frustrated sigh. "Uh... we're gonna need a minute, Cap."
Tony was standing over a holographic workbench. Beside him, Hank Pym—currently shrunk down to the size of an action figure to meticulously examine cellular samples—was analyzing Reed Richards's latest data models.
"We pulled some inspiration from Iceman's cryogenic output," Tony explained rapidly over the comms. "Symbiotes hate fire and sound, but they still have to obey the basic laws of thermodynamics. If you drop the ambient temperature low enough, their molecular kinetic energy slows down. Reed is trying to synthesize an anti-symbiote polymer aerosol based on that principle."
"And?" Steve pressed, bashing a symbiote away with his shield.
"And," Tony grumbled, "our current prototype only delays their cellular regeneration by exactly twelve seconds. It's a band-aid on a bullet wound."
Steve exhaled sharply. A twelve-second delay wasn't going to stop a dragon. They were entirely on their own.
Back at the front line, Goliath peeled himself out of the ruined skyscraper, shrinking back to normal size to recover. Iceman immediately stepped up, riding a slick pillar of ice into the sky and desperately firing massive, sub-zero glaciers to trap Grendel's wings.
"Guys, I can't find a weak point!"
Ghost materialized next to Steve, her quantum-phasing suit humming. She had just phased directly through the dragon's chest cavity. "There's no host inside! It's not an infected animal. The entire dragon is composed of one hundred percent solid symbiote biomass!"
Suddenly, Emma Frost's telepathic voice exploded like a siren inside the minds of every hero present. Incoming! Brace yourselves!
Iceman instantly threw both hands forward, erecting a massive, thirty-foot-thick wall of solid permafrost just as Grendel unleashed another wave of black fire. The ice wall hissed, rapidly melting under the dark flames, but it held long enough to shield the ground team.
Taking advantage of the opening, the Human Torch, Jack of Hearts, and Living Lightning synchronized their attacks, diving toward the dragon's back in a blinding trinity of fire and pure energy.
It was a mistake.
A massive shockwave of telekinetic force erupted from the dragon's spine, violently swatting all three energy-wielding heroes out of the sky like flies.
From the churning black biomass on the dragon's back, a figure slowly emerged.
Knull, the King in Black, stepped forward. Clad in his jagged, biomechanical dark armor, he looked down at the panting, battered heroes with an expression of profound boredom.
"Truly... disappointing," Knull's voice grated, echoing across the battlefield. "I was led to believe the guardians of this realm possessed actual power. Yet you cannot even halt the sluggish advance of my pet."
Knull reached into the void, drawing a longsword forged of pure, pitch-black symbiote matter—the All-Black.
"It appears your motivation is lacking," Knull sneered, pointing the tip of the dark blade directly at the gleaming pinnacle of Avengers Tower. "Perhaps slaughtering every single fragile, trembling soul cowering inside this spire will inspire you to fight with conviction."
A few blocks away, Peter Parker sat casually in the passenger seat of J. Jonah Jameson's parked, beat-up convertible. He wasn't swinging into action. He was actually helping Jonah adjust the focus ring on his dashboard camera.
Jonah paused, looking at the vigilante in utter bewilderment. "You don't seem particularly worried, Spider-Man. That pale vampire is about to crack open that tower like a tin can."
"Didn't you hear it, Jonah?" Peter asked calmly, leaning back against the leather seat. He couldn't exactly explain that his hyper-sensitive spider-sense had just completely deactivated, replaced by the distinct, ozone-heavy scent of a brewing storm.
"Hear what?" Jonah barked.
The answer arrived before Peter could speak.
A blinding, kaleidoscopic beam of pure, multi-colored light—the Bifrost—slammed down from the heavens, piercing the thick, ash-choked sky directly in front of Avengers Tower.
Instantly, the atmosphere violently shifted. Endless, roiling black thunderclouds swallowed the morning sky over Manhattan. The air pressure plummeted. Searing, brilliant forks of blue lightning arced across the firmament, illuminating the dark city in jagged, strobe-light flashes.
KRA-KOOM.
A thunderclap of apocalyptic proportions detonated over the island.
The sheer, concussive acoustic force of the thunder rolled through the streets like a physical tidal wave. The basic symbiote minions clinging to the skyscrapers didn't even have time to shriek. The localized sound wave violently ruptured their unstable cellular structures. Thousands of black symbiotes instantly disintegrated into ash, peeling off their terrified human hosts and blowing away in the wind.
Only the grayish-white elites, spawned from Riot's fire-and-sound-immune Codex, survived the blast. Like vampires caught in the sunrise, they immediately abandoned their hunt and scrambled wildly toward the safety of Knull's throne at the ruined docks.
The blinding rainbow bridge faded away, leaving a single figure hovering in the storm.
Clad in gleaming, silver-scaled armor, a scarlet cape billowing wildly behind him, the God of Thunder gripped the leather-wrapped handle of Mjolnir. Lightning crackled across his golden hair and sparked from his bright blue eyes.
Thor raised his hammer, pointing it directly at the King in Black.
"HEAR ME, KNULL!" Thor's voice boomed, magically amplified to carry over the roaring storm. "I AM THOR! GOD OF THUNDER! SON OF ODIN! PRINCE OF ASGARD!"
Thor brought Mjolnir down, lightning violently striking the pavement below. "AND THIS WORLD IS UNDER MY PROTECTION!"
Standing atop the dragon, Knull narrowed his void-like eyes. He stared at the glowing hammer, a flash of ancient recognition crossing his pale face.
The thunder. The lightning. It was the exact same divine power that had struck his dragon in the medieval age, severing his connection to the hive-mind and burying Grendel in the ice.
Knull's frown slowly twisted into a dark, knowing smile.
He didn't charge. Knull simply raised his hand. Grendel obediently beat its massive wings, turning away from Avengers Tower. The dragon carried the King in Black back toward the ruined docks, landing heavily before the pitch-black throne forged from the Helicarrier.
Riot stepped out of the shadows, kneeling before the throne as Knull sat down.
"My Lord," Riot hissed, confused by the retreat. "Why do we fall back?"
"Gods are exceptionally troublesome pests, regardless of the realm," Knull murmured, resting his chin on his knuckles. "Even Grendel is not guaranteed a swift victory against that hammer. But no matter. This conquest was proceeding far too smoothly anyway."
Knull smiled, clapping his pale hands together once.
From the heavy shadows behind the throne, the massive, corrupted symbiote-Hulk stepped forward, a guttural, terrifying roar vibrating its chest.
"Besides," Knull purred. "We have our own monster to deal with the so-called God of Thunder."