Sonic rushed up the side of the building. He had to get there quick. He pulled himself up through the hole in the wall, and frantically searched for Tails. He overturned the rubble to find the Tornado completely demolished, but no Tails. "Tails?! Tails are you in here?!"
"Target Located." Sonic felt a blast of energy hit him, and he slammed into the floor, the stone cracking around him. He stumbled to his feet, only to be catapulted forward by an unknown force. He slammed through several rooms, still feeling the force push him forward. It finally stopped when he reached the end of the building, but the momentum continued, slamming him into a wall, then finally landing on the ground. Sonic's body hurt immensely, but he stood up regardless.
His vision cleared up, and he saw his attacker standing before him. The machine Eggman had created to be just like (if not better than) Sonic. Metal Sonic.
Shadow tore through the hoards of robots fiercely, with Knuckles helping with the bots. This was child's play to the ultimate lifeform. He could do this all day and not even break a sweat. Knuckles didn't seem like it bothered him much either. The only thing that annoyed him, was that he didn't know where the robots were coming from. Suddenly, there was an explosion, and shards of metal rained from the sky. Shadow looked up, only to see the Tornado slam into the side of a skyscraper. "Knuckles, stay here and deal with these robots! I'll go check out the explosion."
"Since when do I take orders from you?"
"Stubborn bastard.", Shadow thought. He sped off towards the Tornado.
Sonic side-stepped a blast from Metal Sonic and retaliated with his signature Spin-Dash. Metal dodged the attack, grabbed Sonic by the tail, and launched him back at the ground. Sonic landed on his feet gracefully. Metal Sonic had been upgraded since Sonic, and his last fight. Sonic wouldn't be able to handle this on his own.
Eggman watched the attack progressed. Everything was going according to plan. Shadow was going to investigate, just as Robotnik had intended him to. Soon phase two would commence. It was only a matter of time until he got what he needed. They would pay then.