Shadow the Hedgehog as a character was first introduced in 2001's Sonic Adventure 2 as the 'Ultimate Lifeform', before appearing in his own standalone game in 2005 where he notably wields a gun.

The sequel, Sonic the Hedgehog 2, introduced other characters from the Sonic video games, including Miles "Tails" Prower, voiced by Colleen O'Shaughnessey, and Knuckles the Echidna, voiced by ...