User blog comment:CesarTeamHYRO/Random Art for SNN Users to enjoy/@comment-72.191.49.218-20111123015800/@comment-72.191.49.218-20111123023558

Myself 123, good question.

Knuckles: In this world, Sonic and Knuckles never became friends, so when the planet was taken over, Knuckles sided with Eggman.

Rouge: Rouge is in charge of the planet police, the Mobius Police Force, or the M.P.F. and she was hired by Eggman to find out who the Blue Lightnings are.

Shadow: Shadow was cloned from Sonic's DNA and created by Eggman.

That's why.