OGL and Works of Fiction Question

[Fiery Diamond]

So I've been reading different posts here about OGL and writing works of fiction, like novels. I'm currently working on a novel that is partially based on a Pathfinder campaign I was in and thus draws very heavy inspiration from how Pathfinder works.

I've taken care to not use any Pathfinder setting. I've changed names of spells of OGC names to my original names. I've even changed names of various classes.

However, certain game features are fairly obviously present, like limited number of spells per day, the difference between prepared casters and spontaneous casters, my "force missile" spell acting like magic missile in that it increases the number of missiles per casting as the characters grow more powerful, "divine artists" being able to channel unholy/holy energy to harm/heal in a burst.

My question is this: given that certain OGC game mechanics are implied but not directly stated, is this still something that requires me to affix OGL or not?

[Vic Wertz]

First: I'm not a lawyer; I'd recommend you consider consulting one that specializes in intellectual properties law. Second: The OGL is Wizards of the Coast's license, not Paizo's, and I cannot speak on their behalf.

That said, copyright does not protect “ideas, methods, or systems” (copyright.gov/circs/circ31.pdf). Rather, it protects specific “tangible expressions” of ideas, methods, or systems (copyright.gov/circs/circ01.pdf). It also doesn’t protect *short* expressions, such as names or "brief combinations of words” (copyright.gov/circs/circ34.pdf). (Ideas can be protected by patents, and names and brief combinations of words can be protected by trademarks, but the only D&D game term I'm aware of being trademarked is “Dungeon Master.”)

So nobody can own the idea that a Fireball is spell that a wizard casts to make a ball of flame that burns everything in a 20-foot radius, but Wizards can (and do) own their specific expression of that idea: "A fireball spell is an explosion of flame that detonates with a low roar and deals 1d6 points of fire damage per caster level (maximum 10d6) to every creature within the area."