But then it quickly ends up in a situation, where all third party IPs are banned. This, of course, is unacceptable, because it makes custom map making nearly impossible. When you create a high-quality custom map, you must almost certainly use assets that are not public domain. For example, in the dwarf campaign, we use a custom loading screen, which we have permission to use, and also Carmina Burana O Fortuna, which is available for uncommercial use. There is also a custom song in the credits, which was especially composed for the mod, and so on. All are legal for us to use but not for Blizzard.
It's certainly possible.
However, we can safely consider this a very remote possibility. Sc2 has a similar EULA and a centralized map publishing system, controlled by Blizzard. If we look at the history Sc2 had with similar issues, it seems that very few cases happened where the company intervened. (please also see previous posts in this discussion about that)
Practically, a ban of third party material is unlikely, and will probably be reserved to those cases that appear as "problematic"
(for example for a financial reason. It's likely that the abusive use of "pikachu" could result in having to pay substantial compensations to the owner Nintendo. It's very unlikely that the unlawful use of "some song" composed by MaoLi (third party) for Tommi Gustafsson's Dwarf Campaign will end up in owner MaoLi being able to obtain substantial compensation ----> a map with pikachu gets probably banned, a map with MaoLi's "some song" is probably just ingored)
I trust you see my point here.
This draconian EULA is not an automatic ban on all third party content that for some reason wouldn't be correct to use in maps.
This draconian EULA's management of third
party content inserted into maps by modders
is a leverage, that most likely will be used to dodge potential monetary compensation requests by powerful copyright holders whose stuff has been put into maps by modders.
If you imagine being Blizzard, it's very logical and common sense that you protect yourself from potential lawsuits originated by a modder you have no control over.
From what i can speculate, they will ban third party material only when it becomes inconvenient for them. They won't ban your carmina burana until some producer threatens them to pay for it.
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On the other hand, the "all your custom games are belong to us" affecting your original art, narrative and code creations, united to that ninth comma you have brought to our attention:
9. The right to create derivative works, and as part of this Agreement, you agree that you will not create any work based on the Platform, except as expressly set forth in this Agreement or otherwise by Blizzard in certain contest rules, Blizzard’s Fan Policies, or addenda to this Agreement.
These are really concerning and utterly destroy your authorship,
even on derivative work made outside of the platform.
I said this before, it's not sure that such high demands are actually enforceable in court, but if you value your authorship and want to mod this videogame, be sure to take precautions. I am no lawyer but I completely agree with the common-sense advice to protect your authorship given on page 2 by Blarto (can't thank the guy enough):
Here is my advice to people who wish to continue making maps in a relatively serious capacity:
1) Do not use lua, use jass + vex opt (that way blizzard can only steal the optimized jass script which is practically worthless)
2) Use version 1.26 + JNGP for map making, that world editor is stable enough and is under old EULA so you can ignore the new one, and shift the responsibility of hosting the map on the users. This way you can remain anonymous and immune to any C&D. 1.26 is compatible with everything, and if blizzard blocks that option, they delete 10000+ old maps, which is auto rip WC3 for most people. Not a remotely impossible scenario given what I wrote above.
3) All content you make (story, character-names, theme, models, sounds, textures) must be made in third party tools first, and copyrighted in that form (either poor-man's copyright or legit one), in according to your own country's laws. That way you become immune to people copyright trolling you, as you can actually tell blizzard you own the IP. I have no clue how to achieve this, or if this is even worth it.
4) if you are using ripped content sounds/models etc, distribute that as "addon" content that people can download separately and then install it on their wc3. Do not advertise it on the map itself, advertise it in your map's discord. For example Tohou shrine defense map does this with their model packs. Blizzard might block that option in the future by disallowing loose files. As of Jan 2020, this is still possible. This option combined with option 3 makes you completely immune from any copyright issues, but new users might be confused as to why their Goku model is a footman for example.
The only thing I would add is: if you follow point 3 and copyright custom assets before putting them into a map, it's safer that someone else other than the actual mapmaker copyrights those.
Due to the wording of the eula, if the mapmaker himself is the copyright holder, he donates that copyright to Blizzard (see the "custom game acceptable policy"/EULA:
Custom Game Acceptable Use Policy - Blizzard Legal under cooma 1 "ownership").
If the copyright holder is a different person than the one who creates the map however, then that copyright is safe from the EULA's reach.