Below the aerial combat, Sokovia was becoming a different kind of battlefield.
The Ultron army had stopped waiting. Units moved through the partially evacuated streets in coordinated sweeps, and the ones that still had civilians in their path weren't distinguishing between Avengers and bystanders anymore. The evacuation had been nearly complete — nearly. The pockets that remained were the ones that were always hardest: people who couldn't move fast, people who had gone back for something, people who had been caught between corridors when the army activated.
Hulk came down from altitude like a green comet and hit a unit cluster in the middle of the street, the impact radius clearing a ten-meter circle instantly. He came back up with pieces of secondary adamantium in both fists, looked at the next cluster, and threw them. Two units went down. He was already moving.
Wanda worked the approach corridors. She'd stopped using the mirror space — too slow for the scale of the engagement, and every minute she spent contained in that pocket reality was a minute she wasn't protecting the streets. She pulled Ultron soldiers apart with chaos magic instead, methodical, both hands moving through sustained engagement. The magic missiles she kept in orbit around her body tracked targets automatically, freeing her hands for the heavier work.
The Ultron production rate was the problem. For every unit the team destroyed, another came off a line somewhere below the city and moved to fill the gap. The army wasn't diminishing. It was holding constant.
Wanda registered this and didn't let herself think about what it meant in terms of how long they could sustain the current rate. She kept working.
Pietro felt it before she showed it. He was three blocks over, at his speed through a residential area, when the chaos erupted behind him: not the tight focused work she'd been doing all afternoon, but a wave that rolled out without boundary or aim.
The red wave rolled outward from Wanda's position. Ultron soldiers within its radius seized, listed, fell. Units in the air dropped. The street around her cleared in every direction for half a block.
Pietro was there in a second.
She was standing. Breathing hard, hands trembling slightly from the output, but standing.
"You scared me," he said.
She looked at him, and the trembling stopped. Not fully — but enough.
He looked her over, nodded once, and ran.
She's afraid for me, he thought, as he hit the next unit cluster and scattered it. She always was. But I'm wearing vibranium. I've trained on the Tower. I can feel ki now, barely, but enough to know when something is wrong with my body's output. He accelerated into the next street. I know exactly what this battlefield looks like. And I'm still here.
Above it, Smith caught a brief read on the chaos burst and located Pietro in the same sweep. Blue, fast, untouched.
He filed it and brought his attention back to the immediate problem, which was Ultron switching to the phase-shift mid-exchange.
The double-headed lance had been a genuine inconvenience — vibranium construction, weighted correctly, driven with the full mechanical precision of a Mind Stone-directed body. Smith had broken it. Ultron had adapted, using the two pieces as separate weapons, and the flanking geometry they produced was more annoying than any single weapon would have been.
And then, when Smith had taken a half-second to confirm Pietro's position, Ultron had used it.
The lance hit him across the back of the shoulders and drove him straight down. The descent was fast and not controlled — not a graceful landing but a cannonball trajectory into a city block that had been clear of civilians since the Baymax evacuation wave. He hit the street and the street lost the argument, the impact crater spreading outward in a ring of fractured pavement and collapsed foundations.
He lay in it for a second. Looked up at the sky through the dust.
Ultron came down after him, Mind Stone already charging.
The yellow beam fired straight into the crater.
Smith's Kamehameha came up to meet it from inside the rubble.
The two beams hit each other at the crater's rim and locked. White and yellow pressed against each other in the air above what remained of the street intersection, neither moving, both generating enough residual output that the surrounding block was experiencing all four seasons simultaneously — the air superheating on one side, the overpressure creating a wind that snapped structural elements off nearby buildings, the ground under the stalemate point glowing.
Ultron watched his beam hold position and increased the Mind Stone's output.
Smith felt the push. Felt his Kamehameha compress back toward him by three feet. Watched the yellow edge of Ultron's beam creep forward.
"Smith Doyle," Ultron said from above, his voice carrying clearly through the noise, "if you move, this pierces Sokovia. It will cut the landmass and send pieces of it down early. Your city experiences its first meteorite impact before I've even finished."
He's not wrong about the physics, Smith thought, the Kamehameha burning steady in his hands. If I break contact, the beam finds the surface and the moving dispersion through the vibranium core does exactly what he's describing. He looked at the yellow beam pressing toward him. He's also trying to get me to take it straight because he thinks the Mind Stone output exceeds my current level.
He let his Kamehameha surge.
The beams returned to stalemate. Then Smith's white beam started moving the other direction, slowly, the yellow line retreating centimeter by centimeter.
Ultron increased output again.
The stalemate reformed.
Smith pushed harder.
The two energies met at a point somewhere between them, and neither could move it further, and then the accumulated force at the contact point reached a threshold and the entire interaction resolved in the only way available to it: catastrophically.
The explosion went upward and outward in a dome of white light that washed across the rising city like a second sun. For three seconds, every shadow in Sokovia pointed away from the city's center. Every person on the ascending terrain, every Avenger, every Ultron soldier, every Baymax unit still moving civilians toward the pickup corridor — all of them turned toward the light.
The shockwave followed the light by four seconds and hit everything simultaneously. Buildings that had been structurally marginal came apart. Buildings that had been solid flexed and held. Steve Rogers was on the bridge with one hand on a car and one hand on a lamppost when the overpressure hit and the lamppost bent and the bumper he'd grabbed came away in his hand.
He watched the car go off the bridge.
He looked at the bumper. He looked at the drop.
I cannot fly.
Behind him, an Ultron unit he'd been ignoring took the opportunity his distraction represented and swung for his head. He brought the bumper up without looking, felt the impact travel up his arms, turned, and threw it. The unit stopped moving.
Thor came down past the bridge in a controlled dive, Mjolnir ahead of him, caught the car by its frame with his free hand, checked the occupant through the window — one woman, screaming, alive — and redirected his trajectory toward the bridge. He came level with the span and threw the car upward in the same motion.
Steve caught it. Caught it with both arms, felt the weight, walked it to the solid section of the bridge and set it down.
The woman inside was not having a good day.
"It's alright," Steve said through the window. "You're safe."
An Ultron unit rolled up beside him. "You can't save everyone."
Steve looked at it. Reached up, pulled it toward him by its head, drove his shield through its chest casing. The unit seized. He released it over the edge.
"You were saying?"
Thor landed beside him, Mjolnir still in his grip. "I was three streets away."
"Four," Steve said. "Come on."
They moved.
Ultron 4 found Thor twenty minutes later.
It wasn't the standard soldier frame, and it wasn't the three models that had already been deployed and destroyed. This was the reserve — secondary adamantium primary structure with a vibranium alloy reinforcement layer in the torso and shoulder housing, built to the tolerances of a field commander rather than a line soldier. Ultron had designed it as a contingency if the Regeneration Cradle had failed to produce the primary body. It hadn't been needed for that. It was needed for this.
It came in from above, grabbed Thor by the collar, and drove him through the exterior wall of the nearest building at speed.
The wall took them both, and the room beyond took them, and the wall on the other side took them, and they came out into an alleyway with Thor in the unit's grip and the unit's momentum still carrying them forward.
It planted him in the alley wall.
Thor got his arm up before the next punch and took it on his forearm, but the force behind it was more than the secondary adamantium bodies he'd been handling. His arm registered the difference immediately. He pushed back and the unit didn't move as much as it should have.
Stronger than the others.
He brought Mjolnir around in a tight arc and felt the unit's grip on him break when the hammer connected. The unit went backward. Thor came forward, hammer rising.
The unit caught Mjolnir.
That was new.
Not for long — Thor had Mjolnir's return enchantment, and the hammer's loyalty was not subject to mechanical grip strength. But for the second it took to recall it, his primary weapon wasn't in his hands, and the unit hit him three times in that second and all three connected.
He went down on one knee. Got back up.
The hammer came back.
He held it up and let the lightning collect — not a directed strike but a sustained discharge, feeding directly into the hammer's head and building charge. The air around him ionized. The alley crackled. The unit came forward and Thor swung with everything the built charge could carry.
The impact drove the unit through the wall it had come from and halfway through the next building.
It was still moving when it hit the far side. Slower, the vibranium absorbing what the secondary adamantium frame couldn't, but moving.
Thor followed it through the wall.
Tony was forty meters above the vibranium core device with Jarvis running continuous structural analysis on the mechanism.
The device was elegantly simple in concept. A vibranium array generating a directed magnetic field aligned with the planet's natural gravitational gradient, amplifying the lift force across the entire geological mass above it. Shut down the array, the lift stops and the city falls. Shut it down wrong — or destroy the array without controlling the energy release — and the stored field collapses instantaneously, which produces a shockwave through the vibranium that would, per Jarvis's modeling, detonate the entire core and evaporate the upper landmass from the inside.
"The reversal option," Tony said. "Flip the field polarity, convert lift to pull, bring it down controlled."
"Analyzed," Jarvis said. "Controlled descent is achievable. The limiting factor is speed. A controlled reversal requires approximately forty minutes to execute safely. At current ascent rate, by the time descent begins, the landmass will be at sufficient altitude that the controlled rate still produces a terminal impact velocity exceeding survivable thresholds."
"So we need to get it down faster than controlled descent allows."
"Correct."
"What if we supplement the descent force? Something external — pushing down from above at the same time the reversal is pulling down."
"Calculating." A pause. "If supplemental downward force can be provided at roughly three times the array's output capacity, the combined rate achieves safe landing velocity before impact. The landing footprint would need to be the original site — the terrain has a natural socket it was extracted from."
Tony looked at his suit's power reserves. At the Seraphim satellite uplink. At the city around him.
Three times the array's output capacity.
"Jarvis, what's three times the array's output with me?"
"More than you have available."
Tony was quiet for a moment. Then: "What about Smith Doyle?"
"That question is outside my modeling parameters," Jarvis said. "But the math is favorable."
Tony looked up at the sky, where two figures were trading exchanges at altitudes and speeds that the human eye couldn't follow cleanly. He keyed the comm.
"Smith. When you're done up there — I'm going to need your help landing a city."
Above the city, Smith stood in the air with the Kaioken dissipated, watching Ultron reconstitute from the blast.
The exchange had told him what he needed to know. Ultron at full Mind Stone output was a genuine contest at Kaioken x10. Not a problem he couldn't solve but sustaining Kaioken while also managing the precision required to fight without damaging the city below was going to be inefficient.
He didn't need to be efficient. He needed to be fast.
Ultron pulled himself out of the building he'd been thrown into and looked at Smith. Whatever calculation had been running in his architecture since the engagement started had arrived at a conclusion, and the conclusion had rearranged his tactical posture from engaged to wary. He'd been designed to adapt. He was adapting.
"The red aura is gone," Ultron said. "Are you giving up?"
"I was at twenty percent," Smith said. "The Kaioken was twenty percent. I wanted to see what you could do with a reasonable benchmark."
Ultron processed this. "Twenty percent."
"Give or take." Smith's expression shifted into something that wasn't quite a smile. "I promised you I'd show you my full power. Here."
He let the transformation come.
It didn't announce itself with drama. The golden aura rose around him and the ki output changed — not a gradual climb but a step function, one state to another, base to Super Saiyan, the 50x multiplier applying in full the moment the transformation locked. His hair went gold. His eyes shifted. The pressure that went outward from him wasn't the clean geometric wave of Kaioken but something older and more total, a fundamental change in the energy signature rather than an amplification of the existing one.
3 billion combat power.
The city shook. Not from Sokovia's own ascent — it shook from this. The buildings that were still standing vibrated at their foundations. Loose material fell from every surface in a ring extending outward from Smith's position. The air at street level compressed in a ripple that knocked Ultron soldiers off their footing across the entire upper terrain.
On the ground, Pietro stopped running.
He looked up. Looked at the golden figure in the sky. Looked at the scale of what he was registering in the air — not numbers, not instruments, just the physical pressure of proximity to something that operated at a different level than anything he'd previously stood near.
He turned back to the Ultron soldiers around him. There were fewer of them standing now.
Barton, on his rooftop, lowered his bow for one second and looked up. Then he raised it and kept shooting, because his job hadn't changed.
Wanda looked up and felt the chaos magic in her own hands respond to what was in the air — not absorbing it, not challenged by it, but recognizing it. Something vast, something aligned with a power system different from hers but occupying the same category of serious. She looked at the golden figure and understood, viscerally, why the Ultron threat assessment had never truly frightened Smith.
Thor felt it through the wall he'd been fighting through, and the sensation resolved something that had been knotting in his chest since the pool of True Sight. He looked through the hole in the wall toward the center of the city, nodded to himself, and brought his attention back to Ultron 4 in front of him.
"My current combat power," Smith said to Ultron, "is 3 billion."
Ultron looked at him.
The number was not a boast. It was information, delivered in the same register as a weather report — here is what exists, here is what you are facing, here is the gap between what you anticipated and what is actually in front of you.
"Impossible," Ultron said. The word came out with the quality of a system running an error check. "The differential between you and every other enhanced individual on Earth — that's not a gap. That's a different category."
"Yes," Smith said. "It is."
He moved.