I noticed in Assassin's Creed : Odyssey that they implemented a feature very similar to Shadow of Mordor's nemesis with mercenaries . By that I mean automatically and randomly generated ennemies with weakness and complex features.

This IGN article seems to confirm this hypothesis :

Game Director at Ubisoft Quebec, Scott Phillips, says the team “Wanted to have a system where the world was constantly living and constantly challenging” players, so they created a dynamic system of mercenaries within the world of Assassin’s Creed Odyssey, somewhat similar to that of Shadow of Mordor’s Nemesis system.Each mercenary has strengths and weaknesses and unique attributes ranging from animal companions and gear to high skill with a specific weapon, and while there are many hand-crafted mercenaries that can be found around Greece,they’re also randomly generated from a pool of modular fight moves and stories as a way to offer a more elite enemy for players to fight.

I was surprised to hear someone from Ubisoft admitting that the feature was similar to what someone else did in a previous game.

I found this American Bar Association article which explains that game rules are not copyrightable :

Section 102(b) of the Copyright Act states: “In no case does copyright protection for an original work of authorship extend to any idea, procedure, process, system, method of operation, concept, principle, or discovery, regardless of the form in which it is described, explained, illustrated, or embodied in such work.”1 In using the word “or,” the statute lists these exclusions—ideas, procedures, processes, systems, methods of operation, concepts, principles, or discoveries—disjunctively. Thus, each has independent force and effect. This means that neither ideas nor functional elements—such as procedures, processes, systems, or methods of operation—are copyrightable.

I won't lie, it is not clear to me even after reading the whole article what is copyrightable and what is not. I decided to look up one of the very best rip-off in history with Instagram's story system and I learnt that since IG's and Snapchat's story system were visually different, it was legally OK for IG to use it.

Could someone shed some light on the differences between software and video game copyrights, or globally anything that could help me understand how copyright works in the video game industry? Specifically whether it is "features" or "code" or something else that is usually copyrighted?

  • 1
    As mentioned elsewhere, "ideas aren't copyrightable, only implementations" (as a crude rule of thumb - exceptions exist). In addition, the description in your quote could just as easily be said to be an evolved copying of Diablo 2's (released in 2000) Unique Monsters concept (uniquely named enemies with greater strength and special buffs). There are other examples as well. Game developers often build upon the work of other successful games when developing their own, and this isn't frowned upon, unless the whole game is basically copied (and even then, sometimes it's just labeled a 'genre').
    – Jamin Grey
    Dec 30, 2020 at 23:48
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    I haven't played AC: Odyssey, but part of the aspect of the Nemesis system (which was mostly intentional marketing hype) was that when a specific enemy defeated you they got more powerful. I don't see that listed here in AC, but even so, Shadow of Mordor wasn't the only one to do that either. Bloodbourne, which came out about the same time (a few months later), lets any generic enemy that kills you (except for bosses), get more powerful and are visually distinguished by glowing eyes. You have to kill them to recover your lost experience.
    – Jamin Grey
    Dec 30, 2020 at 23:55

1 Answer 1


Video game copyrights are really not significantly different from book or movie copyrights. One of the most basic principles of copyright is that one cannot copyright an idea only the words and images used to express an idea. The question quotes 17 USC 102(b) which is the US law establishing this distinction. A Similar plot point or device is not a copyright infringement. Such common tropes as "budding romance obstructed by differing values" is not protected by copyright. Neither, I would think is this device of auto-generated characters in a video game.

One cannot lawfully copy or closely imitate the actual words or images or sounds in someone else's protected work (without permission). That is the essence of copyright. (There are limited exceptions such as fair use / fair dealing.)

What complicates this and confuses many is the concept of a derivative work. When a character or setting is described in significant detail, a detailed, point-by-point imitation of that setting may be enough to make the newer work "based on" the older work, and thus a derivative work. Unauthorized sequels are often held to be derivative works, for example, or unauthorized "guest appearances" in which a well-know or clearly established character from one work is used in another. If a modern detective goes into partnership with Sam Spade, say, or if Spiderman should be an important supporting character in a newly written novel. Similarly a new fantasy set in Tolkien's Middle-Earth or a new comic in Gotham City would probably be derivative.

One of the things protected by copyright is the right to create or authorize derivative works, and courts have held that use of a distinctive character an make a work derivative. But for this to apply the character must be distinctive and recognizable. A general type, such as a detective or superhero (or a large city) is not enough; there must be sufficient imitation to make it clearly the use of a character or setting from a copyrighted work, with a detailed, point-by-point similarity would be needed.

A game feature such as this "mercenaries" concept would not make another work using it a derivative work, or at least I don't think it would. But ultimately such decisions are made by a court when and if a copyright holder sues an alleged infringer. Whether a work is derivative or not is a very fact-based decision, and so the exact specifics of the case may well matter.

If one is considering imitating some general feature of a previous work, it may be wise to consult a lawyer with IP expertise. I am confident that a major game developer or book publisher would have a staff lawyer to review such questions.

  • I understand. Only the expression of said feature could be considered a rip-off, so one would only have to express it purposely differently.
    – Badda
    Dec 29, 2020 at 16:36
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    It's a bit more complicated than that, as while it's not a matter of copyright, in some cases companies have secured overly broad patents on concepts to the point where similar ideas, but not coded identically, have been squashed.
    – SCD
    Dec 29, 2020 at 23:34
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    @Sean Duggan This is true, but as the linked article shows the recent trend has been to reject many such patents. In any case obtaining a patent is a much more involved and expensive process than copyright registration, and does not seem to fit the casual assumptions of the question (that is the assumption that IP could be easily appropriated by a mere claim). Dec 29, 2020 at 23:48
  • If one could possibly have patent an idea or concept in a videogame, I do think it could fit my question. I honestly am too casual to even know it was possible. Should I edit my question to allow some precisions on this matter?
    – Badda
    Dec 30, 2020 at 10:12
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    @Badda Since someone already posted a detailed answer to the question asked I'd suggest that you open another question to ask about the possibility of patenting a game mechanic like this. You can link to this question in that question for context if you want. Dec 30, 2020 at 14:36

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