A skin of the Overwatch Shotgun Soldier, fighting to protect our glorious Combine! The undersuits are based off of Nemez's models.

"Shotgun Soldiers exclusively wield the shotgun. Shotgun Soldiers can be distinguished by their grey and red uniforms and battle armor. Their helmets are slightly darker than the average Combine Soldier, and have blood red/orange goggles. They also bear the Combine Elite insignia on a red shoulder pad, suggesting that they may be a branch of the Combine Elite, a higher ranked soldier variant, or a squad leader." CombineOverwiki

First appearing in Valve's 2007 video game Half-Life 2: Episode Two as the shotgun-wielding soldier of the game's Combine empire, they were added into Half-Life 2 and Episode One in a May 2010 update.