Career
Jonathan Tweet and Mark Rein-Hagen founded Lion Rampant in 1987 while students at St. Olaf College. There, they also met Lisa Stevens who later joined the company. : 232 His article "Egyptian Magic for Call of Cthulhu" appeared in Different Worlds #47 (Fall 1987), the magazine's final issue. : 84 In 1987, Tweet and Rein-Hagen designed the game Ars Magica, a game centered around wizards in the Middle Ages. : 232–233 Tweet left Lion Rampant and briefly left the RPG industry in 1989 to begin a new career. : 234 Tweet wrote Festival of the Damned (1991), an adventure published by Atlas Games for Ars Magica. : 252 Tweet continued to run an game he created called "Al Amarja" for a group in Rock Island, Illinois, and wrote about the game in articles published in Alarums and Excursions; when John Nephew read these articles he wanted to publish the game, and the result was Over the Edge (1992), the first original game from Atlas Games. : 253 His design on Over the Edge notably involved free-form rules and a subjective approach. Lisa Stevens recommended to Wizards of the Coast to have Tweet work freelance to revise the Talislanta rules for Wizards to publish, and also write the first new adventure for their version of the game; Tweet also wrote a revised version of the Talislanta Guidebook (1992), and the adventure The Scent of the Beast (1992). : 277 Tweet wrote the adventure Apocalypse (1993) for the Role Aids line by Mayfair Games. : 169 Nephew and Tweet also designed On the Edge (1994), a collectible card game based on Over the Edge. : 253 Tweet joined Wizards of the Coast as a full-time employee in June 1994, and brought about new product lines for the company beginning with Ars Magica, which Tweet recommended Wizards to acquire. : 279 Tweet designed Everway, which was first published by Wizards of the Coast in 1995. : 254, 280 After Wizards of the Coast moved away from role-playing games, Tweet worked on Portal, a Magic: The Gathering set designed to help new players learn the game.
Tweet was lead designer on the third edition of Dungeons & Dragons. : 286 Tweet, Monte Cook, and Skip Williams all contributed to the 3rd edition Player's Handbook, Dungeon Master's Guide, and Monster Manual, and then each designer wrote one of the books based on those contributions. Tweet oversaw the Chainmail Miniatures Game design team, and Skaff Elias was responsible for the main design work and Chris Pramas created the game world. : 289 Tweet became the head of the miniatures group, and the Dungeons & Dragons Miniatures Game (2003) was the result of the work by Tweet, Rob Heinsoo, and Skaff Elias. : 292 On December 2, 2008, Tweet was laid off from Wizards of the Coast.
13th Age a d20 System RPG, designed by Heinsoo and Tweet was published by Pelgrane Press on August 3, 2013. The pre-release version was a nominee for the RPG Geek RPG of the Year 2013.
In 2015 Tweet published Grandmother Fish, a Kickstarter-funded book described as "the first book to teach evolution to preschoolers". While criticized by creationist organizations, it has been praised by science educators.
In 2018 Tweet, along with children's science illustrator Karen Lewis, released two card games, Clades and Clades Prehistoric. These animal matching games are intended to be used as tools to teach about evolution. Clades Solo, an app version that includes both prehistoric and modern animals, was released in 2019
The third edition of Over the Edge, with a new setting and new rules, was released June 1, 2019.
