I saw this listing Dave Arneson as a writer, but thinking the (game) part is saying he wrote the game the movie is based off of. Not sure what that means for Gary Gygax, or Blackmoor, or any talking with Dave about the movie.
Directors:John Francis Daley, Jonathan Goldstein
Writers:Dave Arneson (game), John Francis Daley (screenplay) | 2 more credits »
Stars:Regé-Jean Page, Chris Pine, Sophia Lillis | See full cast & crew »
That is also IMDB, where anyone with a login can go and add and remove and edit stuff. Not much different than Wikipedia. Maybe someone with an account there should go and add Gary's name to it.