The D&D rules, whatever edition you use, offer a wide range of material for the players and DM to play with. However, it is almost inevitable that the DM will start to look elsewhere or (as has happened with me a number of times) the DM comes across something that he thinks is really cool and that he wants to use in his games. Original ideas are not easy to create, and they often take time and effort to develop into a useable form. It is so often easier to let someone else do the hard work, and then you just use their ideas. In D&D this happens more often than you might think, though the borrowed ideas may come from cultures rather than specific authors. Many monsters and most character classes are based on ideas from history and mythology. The minotaur, medusa and centaur all came from Greek mythology, while dwarves, elves, dragons and giants come from Celtic and Norse mythology. Druids and bards are from ancient Celtic societies (at least in name), paladins came from medieval ideas of combining chivalry with christianity, while fighters, barbarians, wizards, priests and thieves are all multi-cultural and quite obvious. Even the monk has its roots in the Shaolin monks of China and Tibet. The World of Greyhawk has a lot of aspects borrowed from medieval Europe, especially the feudalism and titles of rulers. Technology, architecture and fashion are nearly all quasi-medieval as well. The Forgotten Realms is a little more different, but it still has many similarities with medieval Europe. Cultures can also provide specific personalities, usually in the form of epic heroes, such as Robin Hood, Hercules, Cu-Chulain Hiawatha, Merlin,
Last post I looked at computer games, which have been a perennial source of ideas for me. There are many others, and the ones I myself have enjoyed using are:
- Other RPGs
- Ars Magica
- Empire of the Petal Throne
- Warhammer Fantasy Roleplaying Game
- Films & TV
- The Lord of the Rings films
- Clash of the Titans
- Jason and the Argonauts
- Novels & Short Stories
- Robert E Howard
- JRR Tolkien
- Fritz Lieber
- Michael Moorcock
- Robert Jordan
- Robert Silverberg
- David Gemmel
- Terry Pratchett (if you don't take your campaign too seriously)
- Real Life
- Myth and Legend
- Other Games
- Magic: The Gathering
- Fighting Fantasy Game Books
- Table-top wargames
- Other stuff
The examples I have listed are just a tiny sample. The list could be gigabytes long if I was to put in the effort.
In the examples above I have (with the exception of real life stuff) stuck with the fantasy genre (in its narrower sense of heroic fantasy/swords and sorcery). However, any DM worth his salt can borrow and adapt from a wide range of genres including science fiction, hard history, superhero, modern day, horror, crime and detective fiction, war stories and travel writing. The internet (in case you hadn't noticed) has lots of cool stuff dotted about the place if you can filter out the huge amount of crap that usually obscures the good stuff.
Borrowing ideas from cultures has one big advantage: nobody owns those ideas. Nobody has copyrighted Roman Gladiatorial combat, the ancient Pyramids of Giza or the system of medieval heraldry (though I believe specific coats of arms may be protected by law). You can use them as much as you like. The only problem is that if you know about them, it is quite likely that others will too. In terms of publishing, this means that others will have probably used the idea before you, and you won’t seem so brilliant if you present something that other people have already produce their own versions of. In terms of your own home campaign this means that your players may know about it as well as, if not better than, you. Running a setting based on medieval Japan would be cool, but if one or more of your players know more about medieval Japan than you do, they may well anticipate your “surprises” (“guys in black pyjamas with black balaclavas throwing small metal stars? They’re probably ninjas. Lets beat them up and get us some experience points….”) or even worse, start correcting you on the finer points of Japanese etiquette.
If you simply want to use the borrowed ideas for your own games with your friends, then by all means go wild.
If you want to publish, even on the internet, be very careful. Folks who make a living out producing pieces of fiction or art do not take kindly to other people plagiarising their works. Some stuff is now in the public domain (see wikisource and project Gutenberg for works of writing now in the public domain - stories by HP Lovecraft, RE Howard and Edgar Rice Burroughs).
For stuff that is currently in copyright and used by corporations or even individuals, be very careful. I am no expert in what is considered fair use, so I play it safe. I have written a number of conversions for stuff from both Magic: The Gathering and Fighting Fantasy game books into D&D which I would like to share here but I would rather not get into legal trouble over.
Another consideration which is not quite so serious but worth considering is whether the new stuff is appropriate for your campaign. Sometimes a campaign is as notable for what it doesn't have than what it has. For example, the Dark Sun setting has no deities - the clerics draw their power from elemental sources. The Lankhmar setting and many other fantasy settings do not have demihumans (at least not as player characters). In my own campaign settings some of them do not have oriental characters (no ninja or samurai), while some games such as Empire of the Petal Throne are so completely different from conventional heroic fantasy that bringing in ideas from outside would require careful consideration.