This is a story that takes place before the events of Sonic Adventure, from before Sonic came to the human world. Mephiles made his debut in Sonic the Hedgehog 2006, which is said to be a bad game. But since the events never happened, this is how I think Mephiles might return to games.

Planet Earth year: 1999

Ever since G.U.N. attacked the space colony Ark, one of Gerald Robotnik's experiments, Project: Shadow, has been sealed away for 50 years. But during those years, he was also held captive by G.U.N. and their general. They didn't just hold Shadow captive but they also had their own project on their minds. This was known as Project: G.U.L.F. Aka, Gun's Ultimate Life Form.

With the power held in this hedgehog's body, the scientists have been trying for a while now to create an exact clone of Gerald's experiment. They could have used the real one, but he was deemed too powerful and with his hate for what they did on the Ark, he was left isolated in the arms of G.U.N. Every now and then the Black Comet would secretly visit Earth developing a plan for the Black Arms to take control and would leave before getting caught in plain sight.

Year: 2000 10:40 P.M. Black Comet's last retreat area

One day, researchers of G.U.N. have been working on ways on how they can complete Project: G.U.L.F. They came across a goopy black substance that they believed to have come from the Black Comet. They took a sample of the goop and brought it back to base to study, it was code named Mephiles. Such a word is said to come from the Black Arms' language, meaning power source, which was probably used to power the aliens' weaponry.

The scientists were fascinated that they managed to find something so rare, and they could use it to make their clone come one step closer to completion. Once they used the substance to create an exact clone of Shadow, and was code named; Mephiles, as it was used to create this creature.

He looked exactly like the Ultimate Life Form, but was blue to show it was G.U.N.'s property and was mouthless. But because they knew little to nothing about said used substance, Mephiles wasn't a perfect and was seen as a failure. He couldn't use Shadow's power to use Chaos energy, he couldn't run as fast as him, had weak head protection, and inherited nothing from Shadow except his looks. Because of so, if Mephiles were to go into battle, he would need a strong headgear and possibly a firearm to keep his defenses up.

Year: 2001, 2:12 P.M. Station Square, terrorist attack

"Sir, there's an attack in Station Square! There're people setting up a suicide bomb!" One of the soldiers shouted as the alarms went off. Mephiles had just arrived to hear the news in secret.

He knew they were planning on getting rid of him because they saw him as a failure, because he heard them taking about him unable to prove himself useful to G.U.N. "Terrorist… all soldiers of G.U.N., grab your firearms and stop those maniacs!" Their general yelled as they did what he was told.

Mephiles overheard everything, there people ready to blow up one of the building in the city and they needed to act fast. This was his chance to prove that he was worthy of being one of them, so he had to go help.

2:15 P.M. Station Square's train station

G.U.N. soldiers have already arrived at the scene and were trying to reason with the terrorist, they would always try to understand why they did such actions and possible stop them without force. Mephiles arrived on the scene and saw that they were already in battle, firing bullets and hiding behind broken pieces for protection.

He watched as the fight went on, and he couldn't take it anymore. A dark aura was forming around Mephiles, as the terrorist and soldiers stopped firing in shock. He flew, dark balls of energy formed in his hands, and he fired them at the terrorist, destroying junks of rubble they used for a shield and knocking them back and the guns flew out of their hands. The hedgehog landed and was shocked at what he just did. Mephiles didn't even know he had such power, it was surprise to both him and G.U.N.

Year: 2001, G.U.N.'s base, 12:53 A.M., Mephiles' room

Mephiles had been working with G.U.N. for a year and at first, he didn't think that much about his dark powers, neither did the researchers because he only demonstrated so little of it. But days after he learned about his powers, he began to become concern of himself. He starts to hear voices in his head, from Black Doom and the Black Arms telling him that humans are pathetic and were using him. Since he was on the humans' side at this point, he refused to listen.

As time went on, Mephiles began to become stronger overtime. Learns about his abilities and was assumed stronger than Shadow by far. G.U.N. began to become concern because such strength might bring him to turning against them. Mephiles worked with them for so long, while also being tempted to Black Doom's side. One night, Black Doom had to put an end to this.

'Mephiles…' Black Doom's voice spoke through his head again.

"*Sigh*, let me guess, you're gonna try to talk me into betraying the humans again?" Mephiles asked knowing the answer.

'You must understand Mephiles, these humans, they're using you. You're nothing but a weapon to them.' Black Doom stated. He had one last chance to change the hedgehog's ways, he had to make it work.

"Listen, I have been by their side for a long time. I know that they would never do such a thing to me." Mephiles said getting up, creating a small ball of energy then making it disappear.

'But you must know this. Remember, they created you, but I have the right to be in charge of you since they stole resources from me.' Black Doom said still trying to convince him. 'Where do you think you got such power?' He asked knowing that his power came from the Black Arms.

"I know how I was created. I also know that I was not created from resources to be used as something that a living creature cannot be used for." Mephiles scoffed.

Black Doom went silent, he had one last resort, and it seemed as if he had to use it. '… Do you want to know the truth?' He asked as an image of him appeared behind the hedgehog. It seemed that he finally caught his attention. '… Do you know why they told you to stay away from you know where?' He asked giving Mephiles a flashback.

(Mephiles' Flashback)

"Remember, under no circumstances are you to enter 'this' room right here." The general said pointing at a door that said do not enter.

"A-affirmative." Mephiles said looking at said door.

"Really, you must absolutely, positively, never, ever, enter 'this' room." The general said again, this time sounding more serious.

"A-affir-I-I mean, yes si-I-I-I mean, s-sir yes sir!" Mephiles stuttered promising not go inside.

(Flashback over)

Mephiles remembered. He promised to not go inside there ever, so to break his promise like that, the price could be his own life.

"I… I-I…" He said lost at words.

'That is where the truth lies… which is why they wanted you to stay away…' Black Doom said as his image disappeared.

The hedgehog was going through P.T.S.D. He was curious as to what was in that room and why he seemed to be the only one not allowed to walk in. He didn't know what to do, but for the first time in his entire life, he actually took Black Doom's advice. But he had to go unnoticed, so he started planning his way into the room.

2:20 A.M. Mephiles' mission

Mephiles now wanted answers. Was he a weapon? Was G.U.N. just using him? He had to find out and once he knew the coast was clear, he left his room sneaking across the corridor. He had to be quiet and stealthy, making his way to the one place he was supposes to be. He was successful, but the door was locked with a hand scanner.

Over time when Mephiles was learning about his powers, he found he could manipulate his body and change shape. He thought it might come in handy some time, and now was the time. He changed his hand into the shape and size of G.U.N.'s general, then used it to open the door, changing his hand back to what it was originally was. He entered the room, up ahead was what looked like a chamber, or something holding a creature captive.

The glass was fogged, he guessed it when from being cold. Mephiles wiped a spot for him to get look of the captive, but it was still blurry, making him look closer cupping his eyes with his hands. Just getting a glance of what was inside was enough to shock him.

"T-t-that's…" He stuttered after he saw what looked like another him in the chamber, but it had red on blue along with a mouth and tanned skin. "T-that's… me?" he said as stress was now getting him.

'Who they used to make you.' Black Doom spoke as his image appeared behind Mephiles.

"B-b-but… t-they l-l-l-lied to me?" Mephiles said as his vans began to show through his skin. He began sweating and gasping for air, nothing could stop whatever was going on in his head. "I… I…"

'There's more.' Black Doom said placing his hand on the hedgehog's head around his quills, then sent him Shadow's memories of what happened on the Ark.

He saw Shadow inside one of the escape pods, his closest human friend Maria Robotnik at the controls ready to send him to Earth. Once she pulled the lever, she was shot from behind. After hearing her last words, Shadow was then sent down to Earth. But what shocked Mephiles the most was that the murderer of Maria, was one of G.U.N.'s soldiers.

"N-no… no, no, no, no, NO!" He said now freaking out. His vans were visible, he was grunting, holding his head and stumbling after learning the truth. "N-no… I-I can't be just a…" He said trying to lie to himself, but nothing could stop him from knowing the truth after now.

'You can't change the truth, Mephiles… face it, the humans used you. You're nothing but a weapon to them!" Black Doom said pointing towards him.

"Th-th-they u-used me… I-I'm nothing b-but a weapon to them." Mephiles stuttered repeating what Black Doom said.

'Humans are evil creatures, who need to be destroyed.' Black Doom said as he words were finally getting through to Mephiles.

"H-humans are evil creatures, who need to be destroyed." He said repeating the alien again.

'You were created as a clone of someone who was left to be held prisoner of these humans.'

"I was created as a clone of someone who was left to be held prisoner of these humans." Mephiles' voice began to get more demonic. His form was changing with each repeat he made.

'Humans took away the one he loved.'

"Humans took away the one he loved."

'They have no right to live, we must end them…'

"They have no right to live, we must end them… THEY DON'T DESERVE TO LIVE!"

Mephiles then became corrupted with his power, he attacked everyone in G.U.N.'s base, bringing few to near death. His rage was only growing with each attack, if he was going to destroy the human race, G.U.N. would be the first to fall. But there was a plan for if he did turn on the humans. The researchers have been working on a Scepter of Darkness, a backup for Mephiles' betrayal. They expected it for a long time, so once the Scepter was found under all the rubble, the hedgehog was captured inside.

Mephiles is now sealed away, unable to make contact with anymore humans, and was unusable for G.U.N. after now. He now waits for the day when he can be freed from this prison, so that he could take his revenge on the humans. He was enraged, and so long as he still remembered what he really was made for, he will never forgive the humans ever again.

Well, that's how I think Mephiles could return to games. There are multiple stories that could happen, but this is how I think it could happen. This will be the only chapter, and Project Gulf: Mephiles' return won't be a series. But let me know what you guys think could happen.