Middle-earth: Shadow of Mordor had a killer feature that made it stand out from its contemporaries — the Nemesis system. While Monolith Productions' clever system is an innovative bit of gaming tech, its origins can actually be traced back to a less creative place.

The Nemesis system is a way for a game to track your progress and interactions with the world, and then use that information to breathe life into NPCs.

For example, in Shadow of Mordor, enemies you defeat in battle will remember the event and come back stronger later in the game, calling you out and recalling your last encounter.

This mechanic keeps the game fresh and keeps players engaged in the world, which is by design — perhaps more so than we ever thought.

A former Warner Bros. Games executive, Laura Fryer, has claimed the tech was created in a direct response to the second-hand games market.

At the time, used games were a headache for publishers and developers. Customers would buy their physical games, play them, and then trade them in at retailers, where they'd be sold on with no share going to the publisher.

Apparently, Batman: Arkham Asylum saw a big sales drop, and this was attributed to used game sales soaking up the potential profits.

Many companies came up with workaround measures, such as single-use online passes, but the Nemesis system was Monolith's answer.

"How do we create a single-player game that is so compelling, that people keep the disc in their library forever?" Fryer says in the above video.

"We knew Monolith's game engine wasn't yet capable of having a fully open world like a GTA, and this team wasn't interested in going the multiplayer route. But we still had to solve for the constraint. And this thinking is what led to the Nemesis system, arguably one of the most creative and coolest game features in recent memory."

It's hard to say if this had any impact on second-hand game sales, but it did result in a memorable and innovative system. It's a shame it hasn't been put to use in more games.

Unfortunately, it likely won't be utilised in the near future either, as Warner Bros. holds the patent for the Nemesis system until 2036; who knows what'll happen after that.

[source youtube.com, via ign.com, eurogamer.net]