This is an area that frequently gets bent to people's whims depending on how easily one action or the other can be seemingly ethically justified.
Content creation legality only merits this sort of discussion if you're going to talk about what's actually legal and what isn't. Talking ethics is a different ball of wax, since everyone's ethics are tailored to their best interests...
I am not a lawyer. This is not certified legal advice. Use a lawyer. That said, here goes...
As far as legality goes: copyright is intrinsically granted to original content creation. In it's purest form, this means that the creator (person or company or entity to which copyright was signed to - for the purpose of this discussion, the person) is the sole entity entitled with copying and replicating their own original content. Period. This applies to _any_ original content creation in any medium.
THINGS can be applied to original content BY the copyright holder (even if copyright changed hands afterwards). These "things" are items such as granting of licensed use, distribution agreements, placing in public domain etc. These are all adjustment to copyright, but copyright does NOT get removed. The copyright holder will always have say in how their works get used.
Copyright holder is responsible for enforcing copyright. Unlike trademarks, copyrights don't get lost if not enforced, and are enforceable even post-infringment i.e. if you used a work for 10 years that wasn't yours, and you heard nothing from them, they can still get you...unlike using an existing trademark for 10 years for example (don't know what the exact time limits are). License to use copyrighted works is at the discretion of the holder and they should always be asked prior to using, and an agreement received, ideally in writing, electronically, or at the very very least a verbal agreement with witnesses.
How does this apply to Marathon scenarios or other Marathon related content creation? First of all, ALL content creation BASED on Marathon, characters, and story IS a derivative of Bungie original intellectual property. Technically, all these works should be created with permission from the copyright holder. For M:R for example, we received very specific copyrighted use instructions pertaining to the scope of the project. Content created for M:R is in large part derivative of Bungie intellectual property. We can not, for example, change the M:R single player story, and say that it is Marathon. It would need to be called something else, and permission for that would need to be requested.
In scenario creation cases, content created belongs to the original authors or designated copyright holder, while the Marathon characters, universe, framework is still Bungie property. Your scenario needs to clearly and plainly display that information somewhere...much like most of the b.org sites related to Marathon do, for example. This also applies to M:R, where Marathon specific stuff belongs to Bungie, and content created belongs to the original creators on Team Unpfhorgiven. We have a third (and perhaps fourth) copyright holder with Unreal Tournament...Epic and Atari.
Marathon Scenarios are NOT public domain. You can NOT put a Marathon scenario in public domain unless Bungie also agrees to do so. You can put all content originally created for said scenario in public domain, however you can't put it in the form of a Marathon shapes file, music file, map file etc..that is still original Bungie IP.
In the specific case regarding the Trojan scenario...The copyright holders involved (Bungie and the Trojan creators) do have sole and final say about how their work is represented, and while you might be able to argue otherwise ethically, legally they are the only ones that have ultimate say. If they do not wish to have Trojan playable in AO, you should not make it so.
Last but not least, there's the element of fair use. Fair use is permitted for personal use for many kinds of media. Taking a screenshot of a game and using it as your desktop picture will probably be just fine...Putting it on your website without saying what it is and what it is from, technically wouldn't be...since that constitutes online distribution (even if money isn't garnered).
Finally, Copyright Law is different in every country. The above stated is more or less valid in North America, but there's difference still even between Canada and the USA.
To summarize, if someone creates something, they own it. If someone creates something as a derivative of other IP, they own the creation in conjunction with their presumed permission to do so from the IP their content derived from.
Hope that helps. Sorry for the long post.
