Dimension 20
Dimension 20 is an actual play show produced by and broadcast on Dropout, and created and generally hosted by Brennan Lee Mulligan as the show's regular Dungeon Master. It is an anthology series, with the setting and cast changing between seasons. Most of the games use Dungeons & Dragons 5th edition. Long seasons, featuring a core cast of players in seventeen or more episodes, are interspersed with shorter side quests, featuring a rotating cast in eleven or fewer episodes.
History
Origins at CollegeHumor (2018–2020)
Dimension20 originated as a production for Dropout, a streaming service launched by CollegeHumor in 2018 to deliver content with R-rated material or an unusual format. Dimension20 was among the shows listed for the service when it was first unveiled. The format for the show, with distinct story arcs in different settings, was determined early on in the show's development. The host, Brennan Lee Mulligan, had been DMing since the age of 10 and had a background as a live action role-playing game writer. He had been the dungeon master for a private campaign with most of the principal cast of Dimension 20, only lacking Lou Wilson and Ally Beardsley.The series' launch took place amid a "renaissance" of actual play shows. Mulligan cited a number of existing tabletop shows as inspiration for Dimension20, including Not Another D&D Podcast, The Adventure Zone and Critical Role. One such show, NADDPod, features Emily Axford and Brian Murphy, who would join Dimension20s primary cast. Guests were also drawn from Critical Role and The Adventure Zone early on in the show's run – Matthew Mercer first appeared in Escape from the Bloodkeep and Griffin McElroy appeared in a live episode of Fantasy High in 2019. The full cast of The Adventure Zone appeared in Tiny Heist in early 2020.
The show debuted in 2018 with the first season of Fantasy High. A sequel to this campaign, titled Fantasy High: Sophomore Year, premiered in 2019. Episodes of Fantasy High: Sophomore Year were streamed live on Twitch, unlike the pre-recorded and edited style of other campaigns on Dropout. The season concluded with a two-part finale titled "Spring Break! I Believe in You!", which was streamed remotely due to the COVID-19 pandemic. Announced on the fifth anniversary of Dimension20, a third season of this campaign – Fantasy High: Junior Year – premiered in January 2024.
The launch of the show took place amid financial troubles at CollegeHumor, which had suffered from a pivot to Facebook video in the late 2010s based on inaccurate metrics. By late 2019, InterActiveCorp, the company's owner since 2006, was exploring the sale of CollegeHumor. In January 2020, the Dimension 20 cast was laid off as part of larger layoffs at CollegeHumor. Mulligan was left as the only creative staff member on payroll at the company. The show nevertheless continued production remotely as California's stay at home orders were put into effect. CollegeHumor was rebranded as Dropout and continued to produce content, heavily focusing on Dimension 20.
Return to studio production and success (2021–present)
On May24, 2021, Brennan Lee Mulligan announced that Dimension20 and other CollegeHumor projects would resume production in-person and in-studio, adhering to COVID safety guidelines set by SAG-AFTRA and other film guilds and production unions. The show also began to use rotating game masters for side-quest campaigns in a change announced the following month. The company was able to hire more staff beyond its initial skeleton crew, and was in a more positive financial situation by 2024.Beginning in 2022, Dropout began to auction off miniatures from previous seasons of Dimension20. The proceeds from the auctions went towards funding future seasons of the show, as well as to charitable causes. This began with A Crown of Candy pieces. A Fantasy High auction in 2024 donated 100% of profit to the Palestine Children's Relief Fund, and for the first time included scenery pieces and segments of the Dungeon Master's screen.
During the 2023 SAG-AFTRA strike, production on Dimension20 initially shut down. In July 2023, Dropout CEO Sam Reich stated that as Dropout is not a member of the AMPTP, they "may be able to reach an interim agreement with SAG" which would allow them to resume production. Reich commented, "but we'll only do that, obviously, if we get the blessing of the union and the buy-in of our performers. If not, we have enough content in the can to last us a little past the end of the year". In August 2023, Reich announced that all Dropout shows had resumed production, as it was determined that their "New Media Agreement for Non-Dramatic Programming" was under a non-struck SAG-AFTRA contract.
In January 2025, Dimension20 announced that the original Fantasy High campaign would be adapted as a webcomic, to be released on Webtoon. The series launched on March31, 2025, and is scheduled to run for 61 issues, referred to as episodes.
In July 2025, the Game Changer episode "Fool's Gold" featured a satirical segment titled Dimension 20: On a Bus!, in which Katie Marovitch poorly ran a game for Mulligan along with Jasmine Bhullar, Aabria Iyengar and Matthew Mercer.
Format
The seasons of the show are broadly divided into "Intrepid Heroes" campaigns, which feature a recurring group of six players, and "Side Quests", which feature guest players. Intrepid Heroes campaigns feature Mulligan as the Dungeon Master, along with players Emily Axford, Ally Beardsley, Brian Murphy, Zac Oyama, Siobhan Thompson, and Lou Wilson. These seasons are generally between seventeen and twenty episodes in length, and a campaign setting is sometimes revisited in additional seasons. As of 2025, there have been nine Intrepid Heroes seasons: Fantasy High, The Unsleeping City, Fantasy High: Sophomore Year, A Crown of Candy, The Unsleeping City: ChapterII, A Starstruck Odyssey, Neverafter, Fantasy High: Junior Year, and Cloudward, Ho!. A 2024 Time Quangle live tour in the UK and Ireland also featured the Intrepid Heroes cast and acted as a crossover between the main campaigns. The players drew randomly from their past characters, using bingo machines to set up each show. The Time Quangle performances were recorded, and were released on Dropout throughout 2024.Mulligan acted as the game master for the first four side quests, after which the show started to use other Game Masters for these campaigns, in addition to Mulligan. Aabria Iyengar is the most recurring guest Game Master, having appeared in the role four times. Guest players for Side Quests are generally CollegeHumor alumni or cast members of other actual play shows, however, there are exceptions such as Dungeons and Drag Queens, which featured notable contestants from RuPaul's Drag Race.
Cast members by campaign
Campaigns
The campaigns use the Dungeons & Dragons 5th edition system, with Brennan Lee Mulligan as the Dungeon Master, unless otherwise stated. The DM or Game Master also creates house rules that alter the role-playing game system the campaign is using.| Symbol | Meaning |
| * | Intrepid Heroes campaign; DM Mulligan |
| ^ | Side quest campaign; DM/GM Mulligan |
| § | Side quest campaign; GM Iyengar |
| Δ | Side quest campaign; other GM/DM |
One-shots and live events
Dropout has released multiple one-shot adventures, in addition to their full-length campaigns. Four have been extensions of the Fantasy High campaigns, including Dimension 20: Fantasy High! Live! at The Bell House, Fantasy High LIVE at RTX Austin, College Visit , and Boys' Night! , while two have been continuations of Misfits & Magic, consisting of the Misfits & Magic Holiday Special and Misfits & Magic Live at GenCon 2022.A series of six live non-canonical Dimension20 events titled "Time Quangle" was held in Ireland and the United Kingdom in April 2024. At the start of each live show, performers rolled dice to determine the characters and setting, pulling randomly from five past Dimension20 campaigns: Fantasy High, The Unsleeping City, A Crown of Candy, A Starstruck Odyssey, and Neverafter. Dropout recorded each performance and released them in late 2024 as a six-episode non-canonical "Time Quangle" series. A series finale called "Quangle Quest" was held at the Climate Pledge Arena in Seattle on July 20, 2025, and released on Dropout on December 10, 2025. Equipped with "Bracers of Quangling", the performers could select which of their characters they wanted to play throughout the show.
A performance at Madison Square Garden entitled "Gauntlet at the Garden", continuing the story of The Unsleeping City, occurred on January24, 2025. As the venue's ticketing is managed by Ticketmaster, a surge pricing algorithm meant that tickets were briefly selling for thousands of dollars, at higher prices than comparable Taylor Swift tickets. Dimension20 issued a statement afterwards, indicating that they had been unaware Ticketmaster was operating its dynamic pricing system for the venue, and that they had opted out of that system for all future events. Given that 15,000 tickets sold in four days, the event was expected to be the largest actual play show in the United States.
A live event set in the world of Fantasy High called "Battle at the Bowl" took place on June1, 2025 at the Hollywood Bowl in Los Angeles; it was billed as a canonical event during which either Fabian Seacaster or Chungledown Bim would die. The Battle At the Bowl was released on Dropout on November 12, 2025.