Does anyone know if the Dungeons & Dragons movie from 2000 takes place in any established D&D setting like the Forgotten Realms, or does it take place in an original setting separate from any known D&D universe?
Specifically, Knightfall asked:
I have some questions for you regarding the Empire of Izmer and its characters. Mainly, I want to find out if the Empire was originally from Courtney's homebrew campaign world or if he just made it up for the movie.
To which David Arneson replied:
Although at least partially based on Corey's world Izmer was pretty much made up for the movie. How much so I do not know for sure.
Izmer was meant to be retconned into Arneson's Blackmoor setting:
Since I did all that work, and WOTC scrubbed movie support (Before the movie came out BTW) I added it to my campaign world. [...] I hope to include all this as a supplement to the Blackmoor source book (out next year).
So [Courtney] didn't actually take the characters and places from the film out of his own campaign, as you might expect. Instead [Courtney] based the world of Izmer and Sumdall, where the movie, takes place from one of TSR's older, obscurer campaign worlds, Mystara.
With all that in mind, it's safe to say that Izmer is a standalone setting, based on the Mystara setting (setting used by Courtney), and then Arneson tried to retcon it into Blackmoor setting.
The Dungeons & Dragons movie was not fit into any of the then-existing campaign worlds that had been released by TSR or its successor Wizards of the Coast. There was some tentative talk of using the movie's Izmir setting for multiple future releases, if the movie was a big hit. However, it is unclear whether this would have happened, as the movie release came during the period shortly after Wizards' takeover of the bankrupt TSR, and one of the strategic changes Wizards of the Coast had made was culling the number of campaign settings, which were felt to be spreading the company's material too thinly.
In any case, the movie was a flop, and the full Izmir campaign setting was never released. However, the company did release one module alongside the film in 2000—a Fast-Play adventure. The Fast-Play products, which were one of the new lines Wizards of the Coast introduced in 1999, were billed as complete games, rather than adventure modules, and were designed for totally new players. Each product (including the movie tie-in) contained sufficient rules for playing a stripped-down version of D&D, without having to buy any other products. The hope was that new players would be drawn in through these introductory offerings (like the First Quest line a few years earlier), expanding the D&D player base.
The movie tie-game includes a short adventure in the Sewers of Sumdall.* It provides a tiny amount of information about the Izmir setting, and includes partial statistics for four of the characters from the film. Since the movie was such a disaster, there were presumably not a lot of viewers who sought this product out, and no other adventures or campaign modules describing the setting and its characters were released.
*The product is frequently referred to as if "The Sewers of Sumdall" were its title, but the actual cover title is "Dungeons & Dragons// The Movie."
As far as I know, it is in a setting of its own, created for the movie.
Actually, the page for the film on the Italian Wikipedia states the setting was made for the movie, although it shares similarities with Mystara's nations of Glantri and Alphatia:
(ambientazione creata per il film, ma simile alle nazioni Glantri e Alfazia dell'ambientazione di Mystara)
I have no idea how reliable this information is.