What does JD stand for in Gears of War?

As a keen observer of the gaming community, I've often come across the acronym "JD" in discussions surrounding the popular franchise "Gears of War." However, despite its frequent mention, I've yet to find a clear and concise definition for its significance in this particular game series. Could you enlighten me, what exactly does the acronym "JD" stand for in the context of "Gears of War?" Is it a character's name, a specific term, or perhaps a reference to a certain aspect of the game's lore? I'm eager to understand its significance and how it fits into the overall narrative of this captivating series.