User blog comment:Supersonic13/sonics famliy/@comment-477304-20110124193147

Sonic Underground, Adventures of Sonic the Hedgehog, SatAm (Sonic the Hedgehog)/Archie comics, Fleetway comics, Sonic X and the Sonic Games are all set in completely separate continuities to each other, kinda like different dimensions of universes. It was never revealed who Sonic's father was in underground, and no-one will ever know because the series was cancelled.