Shadow

Shadow the Hedgehog was introduced in Sonic Adventure 2 and was initially not intended to remain in the series. His popularity surprised the Sonic Team, as noted by Takashi Iizuka. Despite dying at the end of Sonic Adventure 2, Shadow's character continued to engage fans and led to collaborations, including a voice role by Keanu Reeves. Sonic Team has allowed fan creations, which raises questions about the franchise's trajectory had Shadow not survived. His continued presence has resulted in various crossovers, including competing in Olympic-level sports against characters like Bowser.