The Echoes of Eternity: The Search for Shadow

After completing their mission, peace reigns across the multiverse. The Prism restored, Sonic and Shadow return to their respective realities, and Sonic rejoins his friends. However, a fracture emerges when Shadow vanishes without a trace. Initially bewildering, the mystery deepens as Sonic and his friends uncover clues, leading them back to the void in search of their lost comrade. Splitting up across different realities, Sonic eventually finds Shadow-but he's not the same. Their reunion is unsettling, but what follows is even more chilling: a horrifying message from Shadow reveals a sinister truth lurking beneath the surface, a truth that may have dire consequences for Green Hill and beyond.

(NOTE: This is not canon to the events in Sonic Prime, simply a fanfiction from a fan of the series :) )