Shadow the Hedgehog was an experiment created by Gerald Robotnik with Black Doom & Scarlet's help to bring "The Ulmaite Life Form" to life, as Shadow and Maria had a close bond. Still, Scarlet the Hedgehog(Shadow's Mom) vanished away as GUN soldiers attacked the base of the Ark, killing Maria. Shadow grew vengeful toward humanity for the shooting. Maria was in a state of cryoprision for 50 years after breaking free from his prison, as someone knew destroying the world was a bad choice, knowing his main goal was to have Maria's central promise to him to make anyone happy, Shadow knew this was Maria's main goal for him, however Shadow redeemed himself and deicide to protect the world from dangerous invasion of black arm mutant aliens from now on.

Here's the bio!

Species: Mobian Hedgehog & Black Arms (approximately 75% and 15%) 

Age: 50+ but actually 18 physically

Alligment: Good(Netural Good) 

Friends:

Sonic(Friendly Rival), Tails(he respects him), Knuckles, Amy, Cream, Big, Omega Rouge(Formerly) Vector, Espio, Charmy, Silver, Blaze, Sticks

Victims:

Black Doom, Dr Eggman, Metal Sonic, Sage, Rouge

Affiliations:

Team Dark(Leader)  
G.U.N

Relatives:

Dr Gerald Robotnik(True Father/Creator)

Black Doom(Creator)

Scarlet the Hedgehog(Creator Mother)

Well thats i have so :p

What If Shadow changed from neutral to Good: My version of Shadow the Hedgehog and his Story & Bio