According to a 1998 The Playstation magazine interview with director/producer/writer Hideo Kojima & designer/artist Yoji Shinkawa, Kojima originally had no intentions of adding the cyborg ninja character design for Gray Fox to the game, but Shinkawa drew that idea "because it's cool". At first, Shinkawa thought Gray Fox should have looked like a normal enemy soldier. He had several different patterns in mind, and thought to try drawing a cyborg-ish and ninja-looking guy, of which that design came out as a result.

Despite Shinkawa wanting his design to become the main character in his own game, it didn't. Raiden, however, became a cyborg ninja in Metal Gear Solid 4: Guns of the Patriots, and later became the main character of his own game in Metal Gear Rising: Revengeance.