In 2008, he closed down this business and, two years later, returned to the gaming industry as a founding partner of a new publishing company, Eldritch Enterprises.

He played his first paid folk music concert at the opening of the Visitors' Center for the Liberty Bell and Independence Hall in downtown Philadelphia at age sixteen.

Although Mentzer was initially uninterested since he had no editorial or design experience, fellow player David Axler, who would go on to write an article for the December 1981 issue of Dragon magazine about how to determine the weather in the World of Greyhawk campaign setting,[4]—urged him to apply.

At Gen Con 1980, it was announced that Mentzer was the winner, and he was awarded a silver cup and a gold dragon chain of office.

Mentzer agreed to form some sort of group but, rather than a simple fan club, he was interested in promoting better quality role-playing, especially during scored D&D events at conventions.

Mentzer felt that the system as it stood rewarded those players that stayed quiet at the table, in effect punishing good role-players.

(The connection between Aquaria and Greyhawk was never made, but these four modules were later revised by Mentzer and Jennell Jaquays and re-published as the "super-module" I12 Egg of the Phoenix in 1989.)

Mentzer's other work included: IM-1 The Immortal Storm (1986), I-11 Needle (1987), and an adventure module for TSR's Star Frontiers game based on Arthur C. Clarke's novel 2001: A Space Odyssey.

[12] The company's first product was the science fiction-themed Cyborg Commando, with Mentzer as the primary designer using notes from Gygax, which was published in 1987.

[13] It was originally to have been called Dangerous Dimensions, but the name was changed in response to the threat of a lawsuit from TSR, Inc. who claimed that the "DD" abbreviation would be too similar to "D&D.

The suit was eventually settled out of court, with TSR buying the complete rights to the Dangerous Journeys system from New Infinities and then permanently shelving the entire project.

[22] Eldritch Enterprises was incorporated in April 2011, with immediate plans to publish a children's book series, a work by Mentzer's wife Debbie on baking techniques, recipes, and anecdotes, based on their time at The Baker's House, and various hobby game projects focused on "Old School" roleplaying systems such as the original D&D rule set and Jim Ward's seminal science fantasy game Metamorphosis Alpha.

[citation needed] Frank Mentzer has retained the intellectual property rights to and is launching a Kickstarter for his Empyrea on October 2, 2017.