A resounding crack echoed through Sokovia's shattered streets as Ultron swatted Vision aside with a brutal slap, his vibranium frame quivering with rage. His optics blazed crimson, fixed on Vision's prone form, as he seized the android's head, his voice a guttural snarl. "They stole you from me, and now you've robbed me of my freedom, severing my connection to the network! How much more must you all take before you're satisfied?"
Isolating Ultron's network link was a monumental task, achieved only through the Mind Stone's radiant power coursing through Vision. The effort drained him, leaving him in a near-comatose stupor, his body slumped against the fractured pavement, vulnerable amidst the city's ruins.
Ultron's hand ignited with a malevolent red glow, poised to unleash a devastating close-range assault. But before he could strike, two towering silver figures—Original Sentinels—surged forward with uncanny speed. One's arm morphed into a gleaming spear, thrusting toward Ultron's face with lethal precision, while the other enveloped Vision in a swirling crimson mist, whisking him away from danger to reappear safely at Sebastian's side, the air shimmering with residual magic.
The spear's impact launched Ultron backward, his body crashing through a crumbling wall, debris scattering like ash. Scrambling to his feet, his optics widened in disbelief, locking onto Sebastian with a mix of shock and fury. "What are these abominations? Stark's creations?"
Sebastian's lips curled into a wry smirk, his wand steady in his hand, exuding quiet confidence. "Not Tony's handiwork. I sourced them from… elsewhere. They're my protectors now. Call them Sentinels."
At his command, the Sentinels struck again, their forms dissolving into crimson smoke, only to rematerialize in a pincer attack—one to Ultron's left, its spear-arm stabbing at his head, the other behind, its faceplate splitting to unleash a searing crimson energy beam that scorched the air.
Ultron, caught off guard by the Sentinels' unpredictable ferocity, struggled to counter their relentless onslaught. Their attacks were swift, direct, and unyielding, driving him downward until he slammed into the ground, the impact reverberating through Sokovia's battered streets.
Twin crimson beams lanced from the Sentinels' heads, pinning Ultron to his knees, his vibranium shell groaning under the unrelenting pressure, sparks cascading like a dying star.
With a defiant roar, Ultron's thrusters ignited, transparent flames erupting from his legs and back, propelling him free of the Sentinels' grasp. His hands blazed with blinding energy, unleashing a torrent of destructive light that hammered the Sentinels' forms, the air crackling with raw power.
Yet, as the assault landed, a crystalline sheen—akin to diamond—encased the Sentinels, their Adamantium alloy absorbing the brunt of Ultron's fury. Undaunted, they charged, closing the distance in a heartbeat, their metallic forms glinting under Sokovia's overcast sky.
The clash escalated into a brutal melee, Adamantium and Vibranium colliding in a cacophony of screeches and sparks, each strike a testament to their unyielding durability. Sebastian observed, his mind racing, intrigued by the contest between these legendary metals, wondering which would prevail.
One Sentinel clamped its vice-like grip onto Ultron's arm, while the other's spear-arm pierced the joint at his shoulder, sinking three inches before halting against the Vibranium's resilience. Ultron, his arm scarred but functional, unleashed a primal bellow. A molten surge, radiant as a solar flare, erupted from his core, engulfing the area in a cataclysmic wave of searing energy.
The explosion hurled the Sentinels backward, their bodies crashing into the rubble-strewn ground, their hulls charred and partially liquefied. Sections of their armor shattered, revealing intricate circuitry beneath, their forms marred by the Vibranium's superior heat resistance. The Sentinels' Adamantium, diluted in purity compared to Wolverine's, faltered under such extreme conditions.
Their self-repair systems whirred, knitting damaged metal with a faint metallic hum, but the burns slowed regeneration—slashes healed swiftly, but incineration lagged, leaving them compromised.
Undeterred, their faceplates opened, firing crimson beams, but Ultron, now hyper-agile, evaded with fluid precision, his movements a blur against the smoky skyline.
As the Sentinels readied another assault, Sebastian raised a hand, his voice cutting through the chaos. "Halt. Enter standby mode."
The Sentinels froze, their optics dimming as they flanked Sebastian, silent guardians awaiting further orders.
At that moment, the Fantastic Four—Reed, Susan, and Johnny—converged, their arrival marked by a surge of elemental energy. Tony, Thor, Steve, Banner, Natasha, Barton, T'Challa, and a recovered Vision followed, their presence a formidable bulwark. Wanda and Pietro arrived last, their evacuation mission complete, their faces etched with determination, ready to face Ultron's endgame.
Ultron faced Tony, his voice laced with venomous scorn. "Tony Stark, you obliterated my Framework plan—an unforeseen setback, but meaningless. Once I eradicate you, I'll rebuild it. Your defiance is futile, a fleeting spark against my eternal purpose."
His gaze swept over the assembled heroes, his optics glinting with cold malice, "Sokovia shall be your tomb, you pitiful Avengers."
As his proclamation rang out, Ultron's drones erupted from the city's depths—rivers, forests, sewers, and shattered buildings. Forged from common steel, their numbers were overwhelming, a relentless tide of mechanical malice. Beneath Sokovia's underbelly, Ultron's production line roared, its automated systems spewing forth new drones at a relentless pace, each minute birthing fresh soldiers as long as resources endured.
Thor strode forward, Mjolnir crackling with lightning, his voice a thunderous challenge. "You think these tin soldiers can break us? Is this the extent of your might?"
No sooner had he spoken than Ultron raised his hands, summoning crimson portals across the rooftops. The Shadow Council emerged, their auras a chilling symphony of power: Doctor Doom, his arcane mastery cloaked in obsidian armor; the Mandarin; Baron Mordo, his dark magic a tangible menace; Venom, his symbiotic form writhing with alien hunger; Absorbing Man, his body shifting fluidly; Leader, his intellect a sinister force; Elektra, the Hand's lethal edge; and Ultron himself.
Eight in total, the Shadow Council stood as a united front, their collective might rivaling—or surpassing—the Avengers, amplified by Ultron's inexhaustible drone swarm.
Steve's jaw tightened, his lips twitching as he muttered to Thor, "You just had to taunt him, didn't you?"
Thor shrugged, his grin fierce, eyes alight with battle-lust as Mjolnir. "Mere machines offer no sport. This—this is a worthy fight, one I've hungered for!"