Au Concept time!

25 yrs later Dark Mobius storyline except in addition to becoming the hero of Mobius when Sonic mysteriously disappears, Shadow also ends up forming a sort of rivalry with Scourge, who continuously antagonizes him and tries to take over Mobius as well. However, instead of Sally marrying Shadow to "fix him", Shadow gains more influence and following than any royalty on the planet, Scourge extends the "twin Kings of our worlds" offer to Shadow, and Shadow and Scourge develop a truce between their universes by getting married.

The former King Sonic returns to "his timeline" to find himself as a barely remembered figure, and to find monuments of King Scourge and King Shadow.