The "Savage Grenadier Elite" was a Savage Locust variant of the Grenadier Elite. The Savage Grenadier Elite has gone savage after the disappearance of the Locust Queen. The Savage Grenadier Elite does NOT appear in campaign at any point.
The Savage Grenadier Elite is Walmart pre-order (Or from EB-Games in Australia, along with Commando Dom) multiplayer character exclusive for Gears of War 3. A "Limited Edition" of the character was also made available to all with the Forces of Nature DLC pack, which added 3 of the Pre-order skins to multiplayer, regardless of how people purchased the actual game. The Limited Edition skins are recolors of exclusive character skins that reflect either the COG or Locust team colors.