You would be wise to invent your own monsters, or create your own versions of traditional monsters from legend and folklore.Īs noted in other answers, no, you are not allowed to use these creatures under Fair Use. If you were to copy content from published D&D books, a copyright suit might force you to stop distributing your game, and leave you with sizable damages to pay, depending on the exact facts.
While the general idea cannot be protected, anything based at al closely on a published description is likely to constitute copyright infringement. New creatures or monsters invented as part of D&D would be fully protected by copyright. This is true even when the creature being described is one from traditional folklore. Note also that the specific descriptive text used in the D&D Monster Manual and other publications is protected by copyright, and may not be copied or closely paraphrased. As the answer by bdb484 says, there seems no plausible case for a fair use exception to copyright here. But images published as part of D&D, or by independent artists, are subject to copyright, and may not be used without permission. Those are in the public domain, and anyone may use them freely. Many D&D monsters and creatures are based on creatures occurring in folklore and myth, such a vampires and trolls. I generally prefer a pretty liberal interpretation of what constitutes fair use, but this just has virtually nothing that would make me comfortable arguing in your favor.
The effect of the use upon the potential market for or value of the copyrighted work: You are trying to create a board game, putting yourselves basically in direct competition with the makers of D&D.
The amount of the portion used in relation to the copyrighted work as a whole: You are apparently copying entire images, though I suppose you could argue that each image is just one small portion of a larger book or website. The nature of the copyrighted work: Works of fiction and art are highly creative works at the heart of the policy for copyright protection. The purpose and character of the use, including whether it is of a commercial nature or for nonprofit educational purposes: There's no indication that your use would be for nonprofit or educational purposes. The factors for fair use are set out in 17 USC 107, and they indicate that the courts would reject your use: The images are copyrighted, and you are using them in a way that would leave you with virtually no argument for fair use.