Question: What game did the writer of "Blackmoor" help co-develop?
Sentence (from "Dave Arneson"): David Lance "Dave" Arneson (October 1, 1947 – April 7, 2009) was an American game designer best known for co-developing the first published role-playing game (RPG), "Dungeons & Dragons", with Gary Gygax, in the early 1970s.
Relevant evidence: Yes