Benjamin Carmine is the younger brother of Anthony Carmine and Clayton Carmine. Anthony was a member of Delta Squad in Gears of War who was KIA by a Locust sniper while trying to fix his jammed Lancer.
He first appeared in the trailer to Gears of War 2 where it appeared that Carmine was to be back. Shortly after, it was let slip that it is actually Carmine's brother in Gears of War 2. He also explains that he is the youngest of the his three siblings; all of them in service of the COG army. He believes that death in battle will bring honor to his family's name.
Gears of War 2
In Gears 2, Benjamin joins Delta Squad early in the game and helps Dominic Santiago and Marcus Fenix through the first half of the game. He possesses a cheerful attitude and a very academic approach to combat, often to the annoyance of his Delta Squad teammates. Despite this, his squad becomes very protective of him (especially Dom), and he proves to be a capable soldier. When Delta Squad is attempting to evacuate out of the destroyed city of Llima, Carmine is hit by gunfire but manages to make it onto the Raven.
However, the giant riftworm appears soon after and bumps the helicopter in mid-flight, sending Carmine down the beast's gullet moments before it turns and swallows the rest of Delta Squad whole, Raven and all. Delta finds him deep in the riftworm's body, but, despite their best efforts, he gets fatally mauled by the native parasites. Before succumbing to his wounds, he asked Marcus to tell his family he loves them. Marcus collects Carmine's COG tags and a letter to his eldest brother Clayton.
In Gears of War 3 and the original Gears of War's Ultimate Edition, Benjamin Carmine is available as a multiplayer skin on the side of the COG. For the original's Ultimate Edition he is in fact the final character skin to be unlocked, awarded for reaching level 60. This is in reference to Anthony Carmine being the final unlockable character skin in Gears of War 3, to whom is unlocked by default in the original. In Gears of War 3 players need only reach level 35 to unlock Ben.