Wizards of the Coast, makers of Dungeons & Dragons, fifth edition, has made a subset of the game's core rules (known as the System Reference Document or SRD) freely available under the copyleft-ish Open Gaming License Version 1.0a. The intention is to allow third parties to develop additional content for the game by "open sourcing" the base rules and allowing people to use those rules in works that must also be licensed under the OGL.

However, what if one wanted to compose a supplementary work for the game ("homebrew", such as a new player race, new class or subclass, or new spell) and wanted to license it under something else (say, a Creative Commons license)? If the supplementary work didn't copy any elements of the SRD but did make numerous references to its concepts, would that be allowed under fair use, or would the work count as a derivative work of the SRD and thus have to be licensed under the OGL?

Examples of typical statements that could be found in such a supplementary work include:

Ability Score Increase. Your Constitution score increases by 2, and your Strength score increases by 1.

You can cast the mage armor spell once and regain the ability to do so when you finish a long rest.

You have advantage on Strength and Dexterity checks made to escape a grapple.

Whenever you cast a spell that deals acid, fire, cold, lightning, or thunder damage, you may replace all instances of that damage type in the spell's description with one other type from that list.

You can speak, read, and write Common and one extra language of your choice.

Whenever another creature casts a cantrip within 30 feet of you, you may use your reaction to make an Intelligence (Arcana) check with a DC of 10. If you succeed, you learn that cantrip and can cast it as a warlock spell until you next finish a long rest.

Note that none of these tell you what things mean or how to do them, leaving that up to the SRD.

In short, does referring to a work's concepts in a new work in this way cause that new work to be considered a derivative of the first?

  • Define what you mean please. Derivative as in how?
    – Putvi
    Oct 30, 2019 at 16:34
  • 2
    @Putvi: "Derivative" as in "derivative work."
    – jwodder
    Oct 30, 2019 at 16:35
  • Are you asking if you can market this game? What are you asking?
    – Putvi
    Oct 30, 2019 at 16:36
  • @Putvi: No, I'm asking if I can write new content for the game that is licensed under something other than the Open Gaming License. Whether I can do that depends on whether such new content counts as a derivative work of the SRD.
    – jwodder
    Oct 30, 2019 at 16:37
  • Derivative work and all these terms apply to commercial or distributed things, not you playing D&D with different rules, is why I am not understanding.
    – Putvi
    Oct 30, 2019 at 16:38

3 Answers 3


Game mechanics are not normally covered by copyright protection.

boardgames.SE Q: What aspects of a game are not protected under copyright?


I don't mean this offensively, but the term derivative implies you are using the original work in some way. You have said you are not using the original work, so just by definition it can't be derivative.

You are just writing a work of fiction, if you don't use the original work in any way.


The structured the quoted statements is clearly derivative

Wizards of the Coast own the copyright in the way the rules are presented even though the rules themselves are not copyrightable. If your “home brew” is structured the way they structure it (as it is in your examples) then it is a derivative work and you must follow their license.

  • 1
    Tons of RPGs use attribute titles with a short description following it. Are those games infringing in your opinion then? No one has ever made a claim that they are.
    – Putvi
    Oct 30, 2019 at 22:21
  • That makes this answer clearly wrong.
    – Putvi
    Oct 30, 2019 at 22:36

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