Spoiler Alert: This article contains spoilers for Sonic the Hedgehog 3!Shadow the Hedgehog plays a large role in the story of Sonic the Hedgehog 3, but should next appear in a spinoff movie, rather than returning in the sequel. The third installment in the Sonic movie franchise sees Team Sonic coming together again to battle a new antagonist, Shadow the Hedgehog, who has awoken from a 50-year-long animated paralysis and seeks revenge on humanity. Keanu Reeves joins the Sonic 3 cast as Shadow, and the movie displays the hedgehog’s impressive skills in speed, strength, and agility, proving Shadow is just as powerful as Sonic (Ben Schwartz).

https://screenrant.com/sonic-hedgehog-4-shadow-not-return-spinoff-better-op-ed/