Warner Bros Interactive Entertainment has been issued a patent for the Nemesis AI system found in Middle-Earth: Shadow of Mordor and its secret.
According to IGN, the patent protects the "Nemesis characters, nemesis forts, social vendettas and followers in computer games."
This encompasses a hierarchy of procedurally-generated NPCs that interact with and remember the player's actions. The patent also covers changes to the NPCs' positions in the hierarchy, as well as their appearance and behaviour, again based on the actions of the player.
Finally, it includes the Social Conquest battles from the 2017 sequel Shadow of War, which allowed players to use these NPCs to defend their own strongholds and attack those of other players.
The patent will go into effect on February 23 and, providing they continue paying the fees, could be maintained until 2035.
Any developers who build game features that include all the above aspects, or enough to risk infringing on the patent, must purchase a license from Warner Bros.
However, studios are still able to create their own systems that are similar but have enough distinct aspects to stand out, such as the Mercenaries system seen in recent Assassin's Creed titles.
Warner Bros originally applied for this patent in 2015, but has been asked to revise and resubmit it several times.
This has been due to similarities with other patents, including ones held by Square Enix, online title Webkinz and mobile title QONQR.