Iron Man: Ultimate Upgrade

Tony Stark stood in his makeshift cave laboratory, the dim lighting casting long shadows against the walls. The hum of machinery filled the air, but his mind raced at a pace that far outstripped the noise.

This wasn't just about surviving anymore. This was about control—control over his life, over the powers he now wielded, and ultimately, over his future.

Tony's thoughts were focused on one thing: the arc reactor.

The electromagnet keeping the shrapnel from his heart had served its purpose for now, but he didn't need it anymore. It would be suspicious if he removed it.

His body, now partly liquid and enhanced with the Upgrade ability, needed more—something that would sustain him indefinitely and allow him to tap into his full potential. His body could adapt, regenerate, and evolve, but to make sure he never ran out of energy again, he needed to integrate the power source into his very cells.

As he set to work, Tony knew that this was going to be no ordinary arc reactor. This would not just power him—it would become part of him.

The secret to this power was his ability to absorb and integrate energy sources directly into his body, making his own form the power grid. There would be no need to recharge the reactor, no need for him to consume food or sleep. His body would regenerate using the energy flowing from the reactor, and everything he needed to sustain himself would come from the arc reactor itself.

Tony began by gathering materials—the high-grade steel, rare earth metals, titanium alloys, and everything else he'd need for the core structure.

The reactor would be built like the original, but with several key modifications. First, he began with the superconducting magnets—the key to containing the power and stabilizing the flow of energy.

Tony integrated niobium-titanium alloys to form the outer shell and core. He needed the superconductors to operate at extremely low temperatures to ensure that the magnetic fields would remain strong enough to handle the reactor's energy output. With his thoughts guiding the process, he integrated carbon nanotubes within the reactor's core. These tubes, known for their extraordinary strength and conductivity, allowed the reactor to generate and sustain high-energy plasma while keeping the flow stable and efficient.

Tony felt the familiar hum of the reactor beginning to form as he used his powers to speed up the process. His Upgrade ability allowed him to merge with the technology, understanding its design on a microscopic level. He could manipulate the materials, merge them into a perfectly aligned structure that would produce massive amounts of energy without the risk of instability. The core itself was simple, a tiny disc-shaped device powered by cold fusion. He didn't have to worry about the plasma escaping—his body's ability to phase through matter and control electromagnetic fields meant he could manipulate the containment system directly, without risk of losing power.

Once the reactor was built, Tony felt the power surging within it. The arc reactor could produce 3 gigajoules per second—that was its energy output, enough to power an entire city for a short time.

But for Tony, this energy was no longer something that needed to be stored or recharged. As he focused on his body, Tony activated the reactor's core. His body absorbed the energy, and a strange hum filled the air. His cells tingled as the energy flowed through his system, integrating into his bio-electrical structure. It felt like his entire body was awakening, drawing on an unlimited source of power that would keep him alive—and thriving—indefinitely.

The key to the reactor was the ability to convert the energy into a usable format for his body. As the arc reactor's energy flowed through him, Tony's regenerative abilities kicked in, ensuring that his cells were constantly replenishing.

The need for food, water, or rest was gone. His body no longer required external fuel—it was entirely self-sustained, powered by the reactor.

However, there were limitations. While the energy was essentially unlimited for his body, the reactor itself had a limited joules per second output. This meant that although Tony had an endless supply of power, he couldn't just fire high-powered lasers or sustain large-scale energy usage for long periods without exhausting the reactor's limited output.

Tony smiled to himself. The lasers he could now fire would be powerful enough to cut through almost any metal, but they were not infinite. He would have to be careful not to overuse the reactor's power in battle, or he might risk exhausting the available output. The energy drain per second was too high for continuous use, especially in combat situations that required rapid bursts of energy.

The real genius of this arc reactor, however, was in its integration. Tony didn't need to recharge the reactor—because the reactor was part of him. It was fused into his body on a molecular level, ensuring that no matter what happened, he would always have access to the energy he needed.

This wasn't just an external power source—it was part of his system, woven into his very cells. His body's regenerative powers allowed the reactor to function without issue.

Tony could feel it pulsing in his chest, constantly feeding him the energy he needed.

But to maintain the illusion for the Ten Rings, he kept the external reactor in place, right where the original electromagnet had been. He would keep the magnet for now, not revealing that he had already healed and removed the shrapnel using his high-speed liquid regeneration.

It was a clever ruse. As far as the terrorists knew, the electromagnet was still necessary to keep him alive. They didn't know that Tony had already removed the shrapnel and integrated the reactor's energy into his body, leaving him in perfect health.

A few days later, one of the leaders of the Ten Rings, a gruff man with a dark scar running down his face, entered the cave again, accompanied by a few armed guards. They had been watching Tony closely, unsure of the strange progress he had made.

"What is this thing in your chest, Stark?" the leader demanded, pointing to the arc reactor.

Tony looked up with a calm smile, still pretending to play the part of the captive engineer. "It's simple, really," Tony said nonchalantly, "Just a little invention to keep me alive. The electromagnet was doing its job for a while, but this is the only thing keeping me from dying from the shrapnel."

The leader's eyes narrowed. "Why didn't you tell us about this sooner?"

Tony raised an eyebrow. "Didn't think you'd care much about my heart. But I've made a permanent fix for it. You wouldn't understand. Trust me, it's a lot more efficient than whatever you think you know about power."

The leader growled but didn't press further. "Fine. But don't forget, Stark, you're still on a leash here. Don't think we won't find another use for that… thing in your chest."

Tony shrugged, keeping his cool. "Sure, whatever you say. Just make sure you give me what I need to build the missile. I'm not in the business of working for free."

The leader shot him a last, distrustful look before walking out. Tony didn't care. The missile was just a distraction —he was already well on his way to creating something far more important. As soon as rest of materials became present, he would have the armor to match his newfound abilities.