It was just another night in the life of one small alley cat. He was a young tom, not yet in his prime. He had a rather common fur pattern, all black with a white bib on his chest. He was digging around for scraps in a dumpster, when something strange happened. The dumpster was hit by something traveling at high speed. The tom hissed, jumping away until he could assess whether to run or fight. Of course, at this point, the tom couldn't rationalize that far, being a cat. The thing that had run into the dumpster smelled like a hedgehog, but subtly different… for one thing, it was wearing red and white shoes and was blue. The cat went over to the unmoving hedgehog cautiously and sniffed his gloved hand. He nosed him, and mewed at him.
Then came the sound of an engine. The cat turned and laid his ears flat at the sound. It was some sort of flying machine… it stopped, and landed in front of the blue hedgehog. A man, very round, and all in red and black, stepped out and picked up the hedgehog by the back of the neck. In words that the cat could not understand, the man said to the unconscious hedgehog, "So, Sonic… I have finally gotten my hands on you…"
The cat hissed at the man. He didn't smell right. The hedgehog didn't, either, but at least he didn't smell like greed and pride. The man ignored the cat, turning to take the hedgehog back to the flying machine. The cat decided to fight, at that exact moment. He pounced; latching onto the man's leg, and sank his teeth in deep. The man yowled, letting go of the hedgehog. The hedgehog woke from being jarred, and ran off quickly. "You stupid cat!" the man said, after separating the cat from his leg and grabbing it by the scruff of the neck. "You ruined weeks of planning! I ought to destroy you for that! But no… I'm not going to destroy you… I'm going to use you…"
The man grabbed a needle from the flying machine and jabbed it into the cat's side. For a while, that was all that the cat knew.
When the cat awoke, he was acutely aware of a pain in his ear. He was also acutely aware that he was an individual. This was very odd. He tried to scratch his ear, but he couldn't move his paw. He looked down at it, and was extremely surprised by what he saw.
It wasn't his front leg. It was an arm, and it was strapped down on some sort of steel table. He had been changed… he examined the rest of himself. He was wearing white gloves over his paws, but his claws were permanently sticking out of them. There was some sort of metal band across his chest, with shoulder clamps. Most of his left arm was now mechanical, except from the wrist down. As his gaze moved down, he saw that he was bipedal now. His fur was still there, still the same pattern… his feet were apparently changed, because they were in some sort of black and white shoes.
The table suddenly tipped up, and he saw the man from last night. "Sleep well?" the man said, and the cat could understand him. "I hope so. I am Dr. Ivo Robotnik. You are lucky to be alive, after what Sonic did to you."
The cat furrowed his brow… "Sonic?" he asked, and was amazed at how he had spoken.
"Ah, your first word… delightful. Yes, Sonic, the hedgehog, the evil mastermind behind many plans for world dominance! He nearly killed you, when I came and drove him off! It was all I could do to save you, and in order to do that, I had to change you into a sentient form. I'm not surprised you don't remember. You took quite a hit to the head."
The cat gave Robotnik a puzzled look. "I… I don't remember… why am I tied up like this…?"
"To keep you from hurting yourself, of course. Would you like me to let you down?"
The cat nodded. "Yes… I want down… and something to eat…" he said slowly.
Robotnik smiled most grimly. He pressed a button on the control panel in front of him, and the straps holding the cat down were suddenly gone. The cat landed on his feet, his robotic arm held out to absorb some of the impact. Then he stood up slowly. He moved his robotic arm around slowly, all through its motions. It flowed flawlessly. "Why did you save me?" the cat asked.
"First, we need to give you a name. How does Omega sound?"
"Omega…" the cat said, rolling the sound on his tongue, trying it out. "I like it…"
"Good, so your name is now Omega. Well, Omega, I saved you so that you could help me in the fight against Sonic. Will you help me?"
The newly named Omega frowned a bit. Something just wasn't quite right. But he said, "Yes."
"Perfect! Well, now that you've agreed to help me, we'll need to train you to fight!"
Omega spent the next few months training to fight Sonic. He learned to use a weapon, a razor-edged chain. During this time, he noticed that he was still only about half as tall as Robotnik, about as tall as Sonic, he supposed. Mostly, he trained against robots that looked like Sonic, trying to hone his abilities as far as they would go. Finally, Robotnik deemed him ready to go up against Sonic, and gave him a brand new chain, one that was much lighter and shinier than his previous one. "This weapon is an alloy of steel, tungsten, titanium, and vanadium. Unbreakable, and sharp enough to shear through bone! Use it well, Omega…" Robotnik said as he smiled and presented it to him.
Omega nodded as he coiled it at his side. "I will, Dr., for the good of all!"
After that, they departed in a plane for the last known location of Sonic. When they were over the spot, Omega jumped out of the plane, sans parachute. He spread his body out to slow his descent, and eventually landed, cat-agile, but rather heavily, kicking up a huge cloud of dust as he created a small shockwave in the air. He stood slowly, and as the dust cleared, he saw a blue streak approaching from the distance. It was Sonic, of course…
Sonic kept approaching, screeching to a halt in front of Omega. Omega's tail lashed angrily as he addressed Sonic… "Sonic the hedgehog?"
"What's it to ya, Cat?" Sonic demanded, smirking.
"My name is not 'Cat', although I see how you could be confused. My name is Omega, and I am here to stop your reign of terror!"
"Reign of terror? What reign of- oh, I see… you're one of Eggman's creations! Well, that's no problem."
"I'm no robot, Sonic. Just my arm. And now, you die."