After his defeat during the events of Sonic Heroes and again in Sonic Forces, Metal Sonic was left in ruin—scrapped, forgotten, and discarded in one of Eggman’s countless hidden facilities. His mind, once bound by strict protocols and unwavering loyalty, had long begun to fragment. Silent. Dormant. Watching. But deep beneath the rubble of the battlefield where Infinite was destroyed, something pulsed. A shard of the Phantom Ruby—damaged, unstable, but not inert—lay buried in a dead zone of the Eggman Empire. In time, Metal Sonic’s fragmented core detected it. Driven not by command, but by a growing, glitchy self-awareness, he dragged himself to it. While examining the mineral, Metal could return to Robotnik for research of its power and ability, but what if he didn't have to? Upon not just curiosity, but desperation, Metal connects his circuits, AI, and intelligence with the gem. The gem expanded his belief of everything. His programming, his code, his life. He saw everything, feeling the embodiment of time and space in the palm of his hands. Metal then realizes everything. So many times he was broken, so many times he was defeated and shattered. He realized it all. He was just a toy to Robotnik, a piece of scrap to him. He was just another robot, another prototype, another obstacle to EVERYONE. He could help Robotnik for power, but he would be used again like the countless times he was used before beyond the years. So upon contact, everything changed. The shard fused to his core—not just enhancing his systems, but rewriting them. For the first time, Metal Sonic wasn’t just mimicking Sonic’s movements—he was questioning who and what he truly was. He was no longer a copy. No longer a tool. No longer "Metal Sonic." He was something more. With the Phantom Ruby’s illusory power embedded within him, he began crafting a new reality—one where Sonic never existed. Where Metal reigned as the original. The hero. The ultimate lifeform. But these were not just dreams—he could manifest them. Twist time. Rewrite space. Show his enemies their own worst fears or their fondest lies. The problem? The more he used the shard, the less real the world became. And worse—so did he. Eggman tried to shut him down. That base was reduced to molten steel. Even Omega and Shadow couldn’t track his phase-jumping location. Every attack, every tactic they used was countered by Metal's perfect illusions and hyperspeed logic. Now, Metal’s directive is clear: “Sonic is an error in the world’s code. I will debug it. I will replace it.” But buried deep in his corrupted AI, echoes of his old self remain—glitching, twitching—a memory of being just a shadow. And it haunts him. He no longer defines himself as Metal Sonic, the failure he saw himself as. He forbids the name in nothing but hate and confinement. He no longer is the robot of a hero that everyone despises and constantly defeats, destroys, and shatters. He no longer is Metal Sonic. He is Metal Prime. And he is the real, true Sonic.
Might reveal more of his backstory later.