Daniel James Nicholson passed away on april 21st at the age of 72. He was recently diagnosed with cancer. Dan played the first Merchant character in Dave Arneson's Blackmoor campaign, and is mentioned several times in the First Fantasy Campaign and thus one of the first to play Dungeons & Dragons. When the Merchant class was re-introduced to D&D in the Players Guide to Blackmoor in 2006 it was undoubtedly a nod to Nicholson. An obituary can be found here.
Rest in Peace.