Edmund is a young vampire who appeared in the episode Treehouse of Horror XXI during the segment "Tweenlight", as Lisa's crush and boyfriend. He appears to be eight, but is in fact 400 years old.
Behind the Laughter
He is a parody of Robert Pattinson's portrayal of Edward from the Twilight saga. He is voiced by Daniel Radcliffe, who plays the eponymous character from the Harry Potter movies.
It should be noted that both Radcliffe and Pattinson starred alongside each other in the fourth Harry Potter film Harry Potter and the Goblet of Fire with Pattinson playing fellow student Cedric Diggory.