My version of the similarity of Sonic and Shadow.

[Mecha X]

Hello. Here is my version of the similarity of Sonic and Shadow: I recently learned that one of the variants of Sonic Adventure 2, said that Sonic - the second Ultimate Life Form. In Sonic X was a hint of this when Maria sent 2 capsules to the Earth. Maybe Gerald Robotnik, in addition to a hedgehog created another, and maybe it was the hedgehog female. Hedgehog female that was the biological sister of Shady, and no blood Black Arms and super-speed. And when Gerald put in Prison Island, she on the earth fighting with the evil and soon gave birth to Sonic. And maybe the son of Sonic the second Ultimate Life Form and her heir to the strength and speed, and nephew Shady. And perhaps she is either just gone or she is was seized or killed from Eggman's hands.
Disclosure of such stories for me pdrshlo formulas for the anniversary of the game.

[JezMM]

The second capsule in Sonic X contained Emerl if I recall correctly, and even so, it's not canon to the games.  So this idea is just fanfiction really I'm afraid.

[Gatestormer]

I like to believe that Shadow's appearance is based off of the mural of Super Sonic and Eggman in the Hidden Palace. We know Gerald was researching the Chaos Emeralds and had been to Angel Island as he had a shrine replica aboard the ARK. I think Gerald saw the mural and misinterpreted it as a prophecy about himself and Shadow, sort of like Michelangelo's The Creation of Adam.

 

[Monkey Destruction Switch]

^I really like that headcanon. It's not the first place I've heard it. It's fun looking at the mural and seeing how Gerald could get the wrong impression.

I once came up with the following headcanon:

(the image is not by me, by the way; I submitted this headcanon to Hedgecanons)

[Nintarie]

Yeah, I've seen the mural theory before and it's really my favourite, because it feels very plausible.

[Tara]

The mural theory is not only the most interesting of them all, but the one that makes the most sense when you consider that Gerald went so far as to build a replica of the Master Emerald's altar.  It really just shows how much Sega had to work with to make a super-compelling story, but instead decided to just go with aliens and other things that make absolutely no sense in the context of the series.

[Monkey Destruction Switch]

The mural theory is not only the most interesting of them all, but the one that makes the most sense when you consider that Gerald went so far as to build a replica of the Master Emerald's altar.  It really just shows how much Sega had to work with to make a super-compelling story, but instead decided to just go with aliens and other things that make absolutely no sense in the context of the series.

Yeah...I really wish that, in general, the Sonic series would make more use of the things they've invented in the past instead of ignoring it and almost sort of "starting from scratch" with every game.

[Nestor]

We know Gerald was researching the Chaos Emeralds and had been to Angel Island as he had a shrine replica aboard the ARK.

Huh - I'd never thought about that, that Gerald must have actually physically been to Angel Island. It makes you wonder whether he encountered Knuckles' relatives and how that went down.

Either that or Knuckles's relatives had the same revolving-door policy of Master Emerald protection that Knuckles seems to fall prey to - I've got this mental image of the previous guardian standing watch in front of the shrine, complete with a dramatic SA Knuckles-style voice over about his ancient stewardship... all the while Gerald is clambering around the shrine behind him unnoticed with a tapemeasure and notebook.

[GUILD]

I like to believe that Shadow's appearance is based off of the mural of Super Sonic and Eggman in the Hidden Palace. We know Gerald was researching the Chaos Emeralds and had been to Angel Island as he had a shrine replica aboard the ARK. I think Gerald saw the mural and misinterpreted it as a prophecy about himself and Shadow, sort of like Michelangelo's The Creation of Adam.

 

Was this not confirmed at one point or something? Because I've thought "Gerald went to Angel Island during the project's process..yatta yatta...mural...based off of Super Sonic...boom. Shadow the Hedgehog." for a very long time.

Huh - I'd never thought about that, that Gerald must have actually physically been to Angel Island. It makes you wonder whether he encountered Knuckles' relatives and how that went down.

Either that or Knuckles's relatives had the same revolving-door policy of Master Emerald protection that Knuckles seems to fall prey to - I've got this mental image of the previous guardian standing watch in front of the shrine, complete with a dramatic SA Knuckles-style voice over about his ancient stewardship... all the while Gerald is clambering around the shrine behind him unnoticed with a tapemeasure and notebook.

Haven't his relatives been dead for a while now though? xD

[Matthew]

I think Shadow looks like Sonic because the design department in Sonic Team wanted a cool looking villain who would look like a dark reflection of the protagonist, a common trope in game art design. This is why his internal name was Terios, 'reflection'. Sorry to burst your bubble, I think the story is just made up as it goes along

[Monkey Destruction Switch]

Undoubtedly true, but let us have our fun. The joy of headcanons is oftentimes thinking through things more than the actual creators did.

[Matthew]

Yeah, that's true enough. It's the same way I like looking into political conspiracy theories even though I know they are all stupid. That said, I do think it can cause players to perhaps misinterpret the intention of a game's story. Final Fantasy 8 has an infamous theory that some fans seriously believe called 'Squall is dead' which literally hangs on the fact so many fans misinterpreted the story.