Yes. Billy Russo is indeed a character in the Punisher comics. He has a significant impact on the overall narrative and the development of the Punisher's story.
Billy Russo in the Punisher comics is a villain. He has a troubled past and a deep-seated grudge against the hero. His actions drive much of the conflict in the story.
One great 'Billy Russo Punisher' fan fiction is 'The Redemption of Billy Russo'. It delves deep into his character, exploring his complex psyche and his relationship with the Punisher in a really interesting way.
You can find 'Billy Russo Punisher' fan fiction on various fan - fiction websites such as Archive of Our Own (AO3). There are tons of stories there, just search for 'Billy Russo' and 'Punisher' in the search bar, and you'll get a long list of relevant fan fictions.
Sure, Billy Russo is a character featured in the comics. He often plays a significant role in the storylines related to the superhero or crime-fighting themes.
I really liked 'Billy Russo's Hidden Heart'. In this fanfic, the author uncovers a more vulnerable and emotional side of Billy Russo that we don't often see in the original works. It makes you sympathize with his character more.