# Does mentioning Product Identity-protected things in a comparison violate the OGL?

I have a homebrew setting that involves a heavily-modified cosmology. None of my planes are identical to the "standard" planes, and the re-used names are only generic ones with heavily-modified meanings. In fact, the only two with identical names are the Astral Plane and the Abyss.

I would like to publish (on a wiki, and potentially more formally) a concordance of sorts for players more familiar with other cosmologies. Basically, a table mapping my_plane to closest standard_plane(s). This would be both for mechanical purposes (any spell that says it involves the <y> standard plane instead uses the <x> custom plane) and for thematic shorthand (generally, beings who live in the <y> standard plane live in <x> custom plane instead).

Can I, without violating the OGL, actually do this by referencing the actual WotC-published, stock-5e-cosmology plane names? If that's all I do with those names is mention them (without any of the details)?Or is there another sane, understandable way of accomplishing this same task without risking an OGL violation?

From what I can tell, this would fall under nominative fair use as defined in the link:

Nominative fair use permits use of another’s trademark to refer to the trademark owner’s actual goods and services associated with the mark. Nominative fair use generally is permissible as long as (1) the product or service in question is not readily identifiable without use of the trademark, (2) only so much of the mark as is reasonably necessary to identify the product or service is used and (3) use of the mark does not suggest sponsorship or endorsement by the trademark owner.

• I am not entirely sure this is the best place for this question (although I am not going to vote for closing). While it is related to D&D (thus RPG), it is more of a... legal question? And the expertise you are looking for is not exactly the one from people that play RPGs, rather, it's legal advice. Jun 23, 2020 at 3:18
• The reason I am not voting for closing is that maybe you can get the answer from other people that publish similar content (thus being more related to RPGs) or even a random lawyer that happens to be a hardcore RPG player and will be around to answer. Anyway, the LAW.se does exist (law.stackexchange.com) and it might be useful for you. Jun 23, 2020 at 3:20
• Jun 23, 2020 at 3:23
• @HellSaint That (answers from other people who have published stuff like that) is what I'm really looking for. Or that last sentence--other ways to get around the issue and give guidance as to what custom planes relate to what "official" planes. I'd accept evidence from how other settings (which I don't own) have approached the issue. Jun 23, 2020 at 4:00
• @HellSaint I think that there are experienced experts here who have knowledge of the practicalities of publishing adventures. There are a number of people here who have indeed done exactly that. As with the law SE, this site is not a substitute for legal advice from a lawyer. Jun 23, 2020 at 4:00

I am not a lawyer, and I am certainly not your lawyer. I have worked on publications that leveraged the Open Game License, but I was in no way involved in OGL compliance, and in any event none of those publications attempted to do what you are discussing in this question. I offer this as an interested layman’s understanding, and strongly urge you to speak with a lawyer before you publish anything, particularly for sale.

Anyway, from the Open Game License, §7:

Use of Product Identity: You agree not to Use any Product Identity, including as an indication as to compatibility, except as expressly licensed in another, independent Agreement with the owner of each element of that Product Identity. You agree not to indicate compatibility or co-adaptability with any Trademark or Registered Trademark in conjunction with a work containing Open Game Content except as expressly licensed in another, independent Agreement with the owner of such Trademark or Registered Trademark.

The first sentence says that anything published under the OGL cannot “Use any Product identity,” with a capital U in “Use.” That references §1 part g,

"Use", "Used" or "Using" means to use, Distribute, copy, edit, format, modify, translate and otherwise create Derivative Material of Open Game Content.

Referring to something by name is known, as I understand things, as “nominative use,” which probably falls under the definition of “Use” meaning “to use.” (Ridiculous, I know.) I believe that “nominative use” does not fall under creating “Derivative Material,” but I’m not 100% sure of that either. Anyway, normally nominative use is a thing you can do, but the OGL is saying that you agree not to.

Thus, as I have understood things, part of the deal with the OGL is that you can use stuff you otherwise couldn’t, but there is a trade-off where you agree not to do things you otherwise could—which includes this kind of nominative use. So my understanding is that no, you cannot do this under the OGL.

• Can you comment about how the publications you've worked on dealt with such comparisons that would tread close to OGL-violation? Just leaving out such material entirely? Jun 23, 2020 at 17:42
• @BenjaminTHall Nothing I’ve worked on has come even close—we wrote new classes, feats, systems of magic, and so on, but none of those things involve anything that was Product Identity. The only reason I mention my experience at all is that I have mentioned working for publishers elsewhere on the site, so if you dug into my background in response to this answer, you might suspect I was coming from a place of greater expertise than I can claim—and the intro paragraph is, after all, a disclaimer, actively and explicitly noting expertise that I cannot claim. Jun 23, 2020 at 17:51
• Interesting. This would explain why 3rd party publications don't even use the name D&D, even though it is clearly intended for use with D&D (for example, Adventure Modules from Goodman Games say they are for use with "the 5th edition of the first fantasy role playing game"). I always wondered why they couldn't use the name. Jun 23, 2020 at 21:28