See, the creature that is Sonic.exe was created in the void, in a gab between dimensions, making him a non-existent outsider in our universe. This creature was born out of pure dark matter in this void, and at the time he had no real namesake nor did he have an actual describable body, it was only until he learned about OUR world that he actually started getting a body. He learned about Sonic the Hedgehog, and was right there and then a big fan of the series and it's character, ESPECIALLY it's character, Sonic.
So what did the creature do? He used his dark power to copy Sonic's appearance and make it his own, he did exactly what Mephiles the Dark did in the 2006 game, and even when he gained this new form, this creature was something that can only be described as pure evil, this is because he had a monstrous personality: He thought that everything belonged to him and him alone, and as such he gained a childish attitude thinking all intelligent creatures in our world (Namely humans) were to be his playthings for all eternity.
He wanted his own world to rule so his "slaves" would have a place to be in so he could enslave them, so he created his world in a darker image of the Sonic universe, albeit with some of his own added touches to it. The creature had power to alter the very reality of this nightmarish world of his, so it's safe to assume that he is in fact a god in his own universe.
Unfortunately, as omnipotent as this creature was, he didn't have any power to leave his world and enter ours so he could collect his "toys", but he DID have some sort of influence over those with some form of evil in their hearts, and as such the creature was able to get someone (without them knowing) to create a doorway that will bridge the gap between his world and ours. This doorway took the form of a computer game, called "Sonic.exe" which was burned into a CD disc. The Game itself, when played, usually shows the inside of the powerful creature's evil dimension and the creature itself manipulates what goes on inside the game to show what it's capable of. When the game is installed onto the computer, the creature has full control of the hard-drive and everything in it, and eventually when the time is right, he'll come out of the game itself to grab his victims and pull them into his world where he can turn them into his slaves. He can only come out to capture his victims because he has very short time being in the outside world, because he doesn't truly belong in our world.
The creature has never really killed anyone, strangely. Whenever the monster attacks his victims he only goes for their soul and makes the body look like the person killed themselves, though not always, as for the soul he's captured, for some reason he creates a body for the soul he's captured and puts the soul in it, making the person he stole his own little slave.
The way the creature makes slaves is interesting, because when he captures a person's soul he turns it into a Sonic character that the victim favored the most: His victims today take the personas of Tails, Knuckles, Eggman, Sally, Silver, Blaze, Amy and so on and so forth. He mainly goes after video-gamers and Sonic fans but he has a certain hunger for the kind of video gamers who talk smack about Sonic.
As stated earlier, the creature has never killed anyone, but he does butcher and torment his slaves in grisly inhumane manners that it leaves people to wonder if he made his eternal slaves immortal too.
However, when he DOE kill someone, it's probably the most horrific thing anyone has ever seen him do.
He only kills those he's ultimately bored with, and when he does get bored, he turns his own mouth into a black hole and sucks the slave/victim's very existence up. That person who gets eaten by the creature this way is forever gone, never to exist.
Eventually word started to spread about the game disk which contained the doorway into the creature's world, and people started to call it "Sonic.exe" after the frightening game itself. And eventually the creature itself began to call itself "Sonic.exe" or just "Exe", thinking that it's a very fitting name for itself.
As a creature that doesn't exist in our world, Sonic.exe seems to dislike both our God and Satan, seeing them both as unfit masters of the "toys" he's collecting, which would very much explain the Sega 666 in the Sonic.exe titlescreen: It's his way of insulting both God and Satan.
As for his common phrase: "I AM GOD", he only says that because he is in fact a god within his own dark realm, and this fact should not be brushed off or overlooked.
Even though Sonic.exe very much enjoys doing his routine in tormenting people who play his game and then sucking them into his world to be his slaves, he secretly feels that it's not enough, wishing to have full access into our world. He hopes that one day, the doorway between his world and ours will break open, and all of his dark powers will pour out into our world.
Maybe someday, he'll get that chance...
Sonic.exe species is a Demonic hedgehog
will never come to this world because he is not real.
If you are scared easily don't look at pictures