MerricB said:
Tome of Horrors has a problem. The original NG monsters can be redone under the GSL, but the monsters that are the property of Wizards would only be able to be redone if Wizards agrees to it with a new agreement.
Cheers!
I'm not a lawyer, but as far as I understand it, when it comes to IP laws and the OGL, we're looking at three things: patent, copyright and trademark. Copyright ONLY applies if they're directly copy-pasting text; they can steal as many ideas as they want with no problems here. Trademark may apply to a few D&D-exclusive monsters like beholders (the stuff not in the SRD), but they definitely can't trademark fantasy staples like orcs and zombies that predate D&D. (And honestly I'm not sure they've really trademarks beholders and the rest. They consider them "PI" and thus not part of the SRD, but that's not legally binding outside of the OGL.) So what we're down to is patent. Patents have to be registered, and AFAIK Wizards hasn't done this with any D&D rules. (I don't think most RPG rules are even patentable, considering that "mathematical formulas" aren't.)
So if I just took the 4e core books, rewrote the whole thing (no reusing quotes, tables, etc), and snipped out those few trademarked monsters and names, I could publish it and the WotC lawyers would have a hell of a time stopping me.
OGL was intended to establish a clear legal ground for people to make content. I think it's even specifically stated that most OGL stuff may not be protected IP; the license is intended as a positive catchall to assure people that WOTC wasn't going to start battering people's doors down for publishing 3e sourcebooks.
In this case, well, those monsters can only be "property" of WotC if they're trademarked, which they're probably not. (Necromancer will be rewriting rules and flavor text, so copyright and patent law wouldn't apply.)
This is of course assuming Necromancer Games doesn't care if they piss off WotC and is willing to fend off their angry lawyers if necessary, both of which seem kind of unlikely.