TarionzCousin
Second Most Angelic Devil Ever
Essentially, RC could write a Faerie adventure using Spirit of the Century rules, right?While true that Dresden is based on Fate, there's no additional open content in it beyond what's inherited from Spirit of the Century. The intellectual property of the Dresden Files license itself is especially not open for third party use. Fans can do free stuff and share it under the guidelines of Jim Butcher's fan fiction friendly policy, but no 3PP commercial product would be legal.
He can't include any of the characters from the Dresden books unless the product is free.