It has been years since Shadow of Mordor introduced us to the Nemesis System, a dynamic in-game mechanic that turns NPCs into long-term rivals throughout the single-player campaign. Many of us expected to see similar systems appear in other games over the years but there have been very few attempts to create something similar. Now we know why – Warner Bros has patented the idea. As reported by IGN, the US Patent and Trademark Office has granted Warner Bros the patent for the Nemesis system. Up to this point, the mechanic had its patent pending but after five years of attempts, the patent has finally been granted. What this means is that if a non-WB studio developed something similar, they could be open to legal trouble.