Edgar Winterborne was a Fulcrum agent for ten years before it was destroyed. In "Chuck Versus the Fat Lady" he was the Fulcrum agent who was tasked with recovering the list of Fulcrum agents from Team Bartowski.
Later, in Chuck Versus the Goodbye, it is revealed that Ted Roark gave him one of the three pieces to "the key". In that same episode Nicholas Quinn stole it from him in order to make his Intersect work.
He is portrayed by Mark Pellegrino.