Shadow was first shown by Takashi Iizuka for Sonic Adventure 2, he was first shown to the public in a game trailer, but his name was not revealed. GameStop described what little was shown as Anti-Sonic - "similar in appearance, but with darker skin, more angled eyes, a fearsome scowl, instead of Sonic's trademark grin. " Iizuka said that they maintained the mystery around Shadow and had wanted to feature him in his own game since he was introduced. After feeling that it would be inappropriate to give Sonic's character a gun as fans had requested in mailings, Yuji Naka believed that by focusing on Shadow for his own game, they could use his different identity from Sonic to build upon the Sonic brand. The character was featured as a guest announcer and performed other promotional work for the game's release during a wrestling show set up by the Japanese league, Pancrase, in December 2005. Shadow's design was influenced by films such as Underworld, Constantine, and Terminator.