Dave Arneson, American game designer, co-created Dungeons & Dragons (died 2009)

Dave Arneson
David Lance Arneson 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. Arneson's fundamental early role-playing game (RPG) genre work pioneered now-archetypical devices, such as: cooperative play to develop a storyline instead of individual competitive play to "win"; and adventuring in dungeon, town, and wilderness settings as presented by a neutral judge who doubles as the voice and consciousness of all characters aside from the player characters.
Dungeons & Dragons
Dungeons & Dragons is a fantasy tabletop role-playing game (TTRPG) originally created and designed by Gary Gygax and Dave Arneson. The game was first published in 1974 by Tactical Studies Rules (TSR). It has been published by Wizards of the Coast, later a subsidiary of Hasbro, since 1997. The game was derived from miniature wargames, with a variation of the 1971 game Chainmail serving as the initial rule system. D&D's publication is commonly recognized as the beginning of modern role-playing games and the role-playing game industry, which also deeply influenced video games, especially the role-playing video game genre.