When it came time to create comics based on the superheroes in the 1950s, someone was needed to be in charge. Known only as The Legend, he is the man that knows all of the dirty secrets the supes have in their closets. Comics are the official version that the public sees about the supes. In reality, the supes are a bunch of power-driven bastards that abuse it every chance they get. The Legend is an associate of Butcher. The knowledge that The Legend can provide to Butcher and The Boys helps when it comes time to blackmail the supes.
The Legend works out of the basement of Vinnie's Comics, although he originally worked for Vought America