Steffan O'Sullivan is the author of several role-playing game books.
[1]: 319 He designed the FUDGE role-playing game system, first releasing it for free on the internet on December 7, 1993.
[1]: 319 His friend Ann Dupuis wanted to start her own game company, using FUDGE as its flagship game; O'Sullivan agreed, as long as she allowed the game to remain available for free on the internet, so Dupuis formed Wild Mule Games and published FUDGE in a limited print run in 1994.
[1]: 319 Dupuis changed the company's name to Grey Ghost Press in 1995, and convinced O'Sullivan to work up a new FUDGE ruleset, published on the internet in June 1995, and released later that year as the first large-scale FUDGE release from Grey Ghost Press.
[1]: 320 O'Sullivan wrote the Princess Bride role-playing game using the FUDGE system, which was published by Toy Vault in 2019.