A fan of table-top wargames, Arneson began designing his own gaming scenarios from an early age. In 1969 he met fellow D&D co-creator Gary Gygax at the second official Gen Con gaming convention. Collaboration between the two would eventually see the first release of Dungeons & Dragons in 1974.
Dungeons & Dragons established the traditional RPG form, with concepts such as "leveling," "parties" and others all owing their lineage from the game and directly influencing countless computer games.
Arneson joined Tactical Studies Rules (TSR), founded by Gygax and partners Brian Blume and Lorraine Williams, in 1976. After enjoying a period of unexpected success with D&D, Arneson left the company in 1979, filing suit against TSR over crediting and royalty disputes. The legal disputes were settled out of court in 1981.
Though the legal battles caused friction between Arneson and Gygax, the two were reported to be on good terms at the time of Gygax's death last year.
Following his departure from TSR, Arneson went on to found 4D Interactive Systems, a computer company that is still in operation today. He also taught at Full Sail University as a professor of computer game design until 2008.
Arneson is survived by his wife and daughter. An email to Grognardia from Arneson's family contains information on where to send condolences.