A/N: Welcome! I hope you enjoy my first MULTI-CHAPTER story. I'm used to short stories, so please, it would help if you review on how well this goes. :) Happy reading~

Prologue: Sonic's Shadow Surfaces

Dark clouds hovered in the sky, grumbling with thunder. In a few moments, rain began to pour as a freezing mist to the earth below. The tiny pricks of water stung like ice piercing the skin, nearly like chilled daggers. The half frozen water made the ground slick and cold; it was a wonder if anyone would be able to trek through the land to begin with.

Only one person can stand against the harsh weather with a force of his own. His feet blurred together at the blinding speed, the wind ran with him, and his eyes glowed with a flaring determination, set on the path ahead of him. The blue individual narrowed his eyes as a metallic base revealed itself. He made haste and closed the distance and dashed in.

Alarms began to wail to warn of the intruder, but not even that could overwhelm the explosions of robots and the crashing debris of walls being blown through. Egg Pawns ran down corridors with advanced guns and numerous other weapons they were applied with. They were only a mere distraction to the speedster to his goal. He knew what lied in the heart of this base, and there was only one entrance to it.

As he ran farther down the hall, a giant locked door with bolts holding it together was spotted. A throng of robots stood about a couple yards from it, taking aim at the speedster with specialized guns. They rained down bullets upon him. The blue hero only grunted in boredom as he dodged the shots effortlessly. He plowed through the group with a spindash and continued on. His emerald eyes widened in interest as the door he sought for was right before him.

Only one shot, He thought.

His legs picked up the pace to where he felt the barrier of sound deafening his ears. He curled himself into a deadly, piercing ball and forced the door off its' hinges. The giant, heavy door landed with a-slam!-and along with that, some screws bounced with their bright clinks, rolling around on the ground by it's side.

He walks across the fallen door and looked around the room. It had the dome shape and an extremely tall ceiling. A computer was beeping from somewhere, he wasn't sure exactly. From what he could only see, half of the room was shrouded in darkness and the lightened side he was on was clean...such an uncharacteristic thing to see. He wasn't even sure how the lighting was possible to begin with.

"Sonic, look out!" A scream from above warned.

A flash of metal caught his eye and he dived out of the general direction, avoiding a giant claw that was supposed to grab him. The claw destroyed the giant doorway with emphasized long, serrated individual pieces of metal. Metal against metal caused an array of sparks to fly with yellows, reds, and oranges like a geyser. Sonic found it was like his anger, small pieces of ember that could kindle his fury.

A booming evil laugh echoed in his triangular ears. Sonic growled and searched in the shadows. He saw the claw retract and fly back where it came from. A-clunk!-came after, sounding like it was right there in front of him. A hint that the enemy is nearby. Mechanical squeaks and scratches continued to emanate from the dark, the familiar idea the adversary was approaching.

"You finally arrive hedgehog!" Eggman's voice mused, his body still hidden.

"Finally?" Sonic questioned. "I guess you're eager of getting your ass kicked." He was joking around, even though his tone is less so. Sonic was hoping to fool Eggman with his normal attitude when it comes to battling him. It would make it easier for him to vent his anger. No, not anger...rage.

"The only thing I'm eager about is destroying you once and for all!" Eggman retorted. A whirring sound and a gleam was all it took to get Sonic motivated to move. He ducked out of the way and a giant robot slammed into the spot he was previously in. He somersaulted backwards onto his feet and took a look at what is before him. Sonic figured he based it off one of his own robot designs, seeing as the body figure seemed familiar.

A half sphere of glass held the villain himself as the head, one arm was a claw, that in fact attacked him merely moments ago, and the other looks to be a laser gun. The metal skin shone a metallic blue with a mysterious glow. It is typical and simple, which is unlike Eggman, who often shoots to improve his plans and make himself a deadlier threat. It doesn't feel right to Sonic. Something was off and it sent a chilling shiver down his spine.

"You look like you're running low on robot ideas Eggman." Sonic commented.

"Don't be fooled Sonic," Eggman advised. "I have more tricks up my sleeve than you think!"

As if on cue, the robot flashed an electric shield around itself. The bright shock blinded Sonic for a few seconds, giving Eggman an opening. He swung an arm at the hero, slamming him into a wall. Chuckling in satisfaction, he pulled the limb away to reveal Sonic indented into the wall with a mad grin. Sonic's adrenaline filled eyes glistened brightly, a sheen of excitement is all that is there. Eggman slammed his fist down in frustration. It drives him up the wall when he started to use his cocky attitude.

"Is that all Eggman?!" Sonic shouted, peeling himself off and landing on his feet. He winced a little, but he ignored the pain. He didn't mind it; he was going to inflict pain back onto his enemy anyway.

"Is that the best you can do?!" Sonic yelled again, anger hinting his tone. He began to walk to the robot with a determined stride, his grin turning into a frown.

"...Huh?" Eggman uttered. He has never seen him so serious before a battle. Is the bait he used a bad choice?

"You'll have to improve your game if you want to beat me!" Said Sonic.

"I won't need to improve anything brat," Eggman countered, the clawed arm trailing upwards. "I have all I need to demolish you."

The claw kept moving into the shadows high above them, barely light enough to see the outline of the sharp metal. A heartbreaking shriek came from the black side of the round shaped ceiling. Sonic's ears flicked, recognizing the voice and who it belonged to. He assumed at first that he was the one who Eggman taken, but he kept hoping and hoping on the way that he was wrong; unfortunately, he was right.

"Tails!" Sonic called out. He investigated above him to see the young kitsune, but so far, the claw hasn't lowered him back down enough. What he got in reply was a struggled groan; numerous grunts and pants followed after.

"Sonic, help!" Tails pleaded.

"Don't worry buddy, I will get-" Sonic choked in mid-sentence, eyes widening in shock.

Tails was finally brought to the light, revealing his beaten body. His golden fur was dirtied and ruffled, and from what Sonic could tell, a bruise was surrounding an eye. He peered at him, trying to see his condition better. He stepped to the side and discovered a red slash went from his cheek to the edge of his mouth. A crimson drop slid down his chin, dropping down onto on of the sharp, jagged claws. Sonic's eyes followed it's trail down until it hit the hard, metal floor.

Disbelief crossed his face. Tails couldn't possibly be hurt, he is strong, he can handle Eggman and his minions. He has done it so many times in the past...but, majority of these occasions, Sonic himself was also there.

This round, he is rescuing him...and Tails is in much more danger than the previous mission.

"So Sonic, are you going to battle me for your friend or are you going to gape at him in shock the whole time?" Eggman questioned amused.

He couldn't completely register his question. He flicked his sight to the floor to think, to get his sense of sight unfocused to clear his mind; unfortunately, the image of Tails being in pain would not dissipate from his mind. It kept becoming more solid and real. Why won't it leave?! Why would you do such a thing?! Why?!

"You...You hurt him." Sonic muttered shakily.

"What was that?" Asked Eggman. "I can't quite hear you from up here."

"You hurt my brother." Sonic replied louder.

"Yeah, when push comes to shove, you have to keep your prisoners in somehow."

Sonic's hands clenched into fists as his frowned deepened. That was the last straw, in his mind, he will end the beginning of a habit.

His normal green eyes were beginning to lighten to a white, the royal blue of his fur slowly darkening, as well as his peach parts of him. His breathing was becoming rapid and rugged. The control of his temper was slipping...and no matter how much his conscious was screaming at him, he cared less how far he fell.

"S-Sonic?" Tails stuttered.

Tails has never seen Sonic so angry. He knew he was furious when he "entered", but he didn't realize how much of that was deeply boiling underneath his calm facade. He could sense it was there. He just couldn't tell how much it was there and how it is transforming his idol.

"You bastard!" Sonic shouted, his voice suddenly an octave lower than normal. "You will pay for what you have done!"

Eggman jumped at the abrupt change from his nemesis, hitting the control stick for the arm holding Tails and releasing him. Tails gasped and started to spin his twin tails like a helicopter. He slowed his fall enough and landed on his feet, cringing from the shock of it. He faced to Sonic to only find another gasp stuck in his throat.

Sonic is enclosed by a dark navy blue aura, gloves and socks torn, his whole body inverted to a color as dark as night. Tails flinched in fear when glancing upon the whites of his eyes, noticing that the green of it has disappeared. His heart dropped into his stomach taking in the fact that his flamboyant and bouncy quills have upturned.

He couldn't recognize who Sonic is...it was some other guy that swallowed his friend from the inside out and stood in his place.

"For your ignorant and selfish mistake, I will personally fix it by punishment." Sonic claimed. His voice rocked the inside of Tails skull and body. It even shook the glass dome Eggman was held safe inside for the moment, but he moved his robot back for good measure...but mainly out of fear.

Eggman looked at his trembling hands, noting how he couldn't calm himself the slightest. There is no way he could beat him... He has witnessed the power of this form, and being on the receiving end means death.

Only a fool would be stupid enough to challenge him, Eggman thought.

He shakily took the controls and moved his contraption towards the exit. Sonic smirked in delight and dashed in front of him to prevent him from leaving. In seconds, he attacked. Neither men could follow where he burst through or where he was in general. The metal was being dented, holes filled the body, and oil flew and splattered the walls and leaked to the floor. The robot couldn't hold itself any longer and fell frontwards. Tails saw the oil seeping to an open hole where wires were flickering and took cover behind a stack of metallic crates.

He closed his eyes and ears and a minute later, an explosion shook the building. When the vibrations ended, he sighed and opened his ears once again. Maybe Sonic is calm again and they can go home. This scenario can be forgotten and they can be happy again.

He thought this over a few times to calm himself. Tails opened his eyes and bravely walked back into the open and saw the last of the smoke. Two figures were clear as in body shape, one being darker than the other, and one was advancing onto the latter, who was using their feet to push themselves backwards and away from the threat.

The only other people are Sonic and Eggman, and from what Tails could tell, Sonic-if it is even him anymore-is the one standing before Eggman.

"N-No," Eggman begged in anxiety. "Please, I am begging you! Don't-"

SNAP!

Tails felt himself go numb in disturbance from the grotesque sound he just heard. Blood shot out from the smoke, barely missing Tails. A-thunk-was also heard right after the headless body hit the ground. A pool of crimson began to form around the corpse, and it didn't take long to reach the tips of Tails' shoes. The smoke finally cleared and he gone weak throughout his body, slowly backing away. The yellow fox gagged, trying all he could to tear his eyes away from what was Eggman. His back hit the boxes he was previously hidden behind, suddenly feeling like a trapped animal...no matter how true the statement itself is in literal terms.

Sonic, who is still in his Dark form, dropped the head beside the body and walked toward his friend...at least, he takes him as one still. The blood covered nearly all the front of him, matching his malicious and sickening grin. He stopped before Tails, the dripping blood surrounding his shoes.

"So Tails," Said Sonic. "How about we go home and tell everyone the good news?"

Tails was too stricken to answer. His brother has transcended psychotic, but he is acting like he is normal. He knows nothing will ever be the same again...not at all.