How the Nemesis System Creates Stories

If there's one gameplay innovation that I think deserves another look - it's the Nemesis System, which first appeared in the 2014 game, Middle-Earth: Shadow of Mordor. At its most basic, it's a villain generator, capable of populating Mordor with a handful of procedurally generated bad guys. Each one has its own name, look, gameplay traits, and personality - which is revealed in taunting one-liners before combat. HORZA: "I wonder which of us will kill you first…" But at its best - and especially so in the sequel Shadow of War - it's a full on story generator, which is able to spin unique and highly personal narratives from your relationships with these orcs.

It's a pretty incredible feat of design and engineering. We've seen story generation stuff in games like Rimworld and Crusader Kings - but in a real time action game with blockbuster graphics? It's unheard of! It's also something I've talked about a number of times on this channel. But I've never really dug into the specifics of how it works. To be honest, I've always been intimidated by the sheer complexity of the thing.

That is… until now. It's about time I finally gave it a go. So… hi! I'm Mark Brown, this is Game Maker's Toolkit, and here's how the Nemesis System creates stories. A quick note before I start - to save time and make things easier, I'm mostly going to talk about these two games as a single entity - which I'll just call "Mordor". It's worth noting that Shadow of War makes massive changes and improvements to the system, but the broad strokes do apply to both games.

If I had to choose an analogy for the way Mordor tells stories, I'd go with "improvisational theatre", where unscripted stories spontaneously evolve as the performance goes on. And especially the rule "Yes, And…", which is about always accepting your partner's prompt, and building on it. And that's exactly how it works in Mordor. The player does something, the game recognises it, and builds on it. So you might run away from a battle with an Orc captain to save your skin - and get called a coward in a future encounter..

ZÛMUG: "Not letting you run this time! I's gonna finish it!" Or you might put a spy into the enemy's ranks, only for the the next Orc you meet to say… RÂSH: "We know you've planted a spy. Dunno who he is yet. But we'll just torture maggots until we find him". The way this works is that the game is always secretly cataloguing your interactions with the game, and the Orcs can then reference this list in order to choose the most interesting line of dialogue at the start of your next encounter.

And that's really clever because it means the way you communicate to the game - the way you make your improvisational suggestions - is through the most basic actions of play. Things like kill, flee, injure, heal, or gather intel. The things you're doing anyway in order to play the game get used by the Nemesis System as a jumping off point for the narrative. But this can also go the other way, with the Orcs giving prompts - and hopefully the player will take the bait and build on the story themselves.

Take this Olog called Ar-Karo who beat me to a pulp, bent down, picked up my sword, and broke it. AR-KARO: "You think this hurts me? No!" I guess I'll be tracking him down.

Okay, so that's the basics. But this left developer Monolith Productions with a problem - in a game that's all about death and violence, how do you make these stories last longer than a single encounter? You can't have improv if your partner is dead, after all. The solution was to find ways for an encounter to end that don't involve death. So, for one, the player is always able to run away from a battle - and is often encouraged to do so because it's difficult to recover health in the middle of combat.

Some Orcs also retreat when their life is in danger. Also, right at the moment of death, it's possible for the encounter to go a very different way. PRÂK: "I can't go down like this. I won't go down like this!" A downed Orc might defy death and have a tricky escape. Or if the player is about to die, the Orc might decide to just humiliate them and walk away. Take Maku: a wiry little archer who keeps downing me with his poisonous arrows, but always stops short of finishing the job.

MAKU: "Get up man-filth. I want a victory, not a mercy killing". MAKU: "It would be too easy to kill you like this." MAKU: "Come on! Show me some 'Pride of Gondor' or whatever you men are always going on about." But even if Talion does actually die, that's not the end. In almost every game, the player's death is a non-canonical error that gets erased when you rewind to a previous save point. It's rare to find games where the player's demise is actually weaved into the narrative in an interesting way.

But in Mordor, protagonist Talion is a gravewalker: a man stuck between life and death, which gives him the power to endlessly come back to life: like someone re-spawning in a multiplayer match. And this allows for a key narrative trope: revenge. AR-KARO: "I know why you want kill me! Revenge! Revenge for sword! Hahaha!" Oof. Well. He won't be a problem anymore. Monolith says it was inspired by the Burnout games, where you can get wrecked by rival racers - and then you're dropped straight back onto the track so you can hunt down that car and enact some sweet justice.

It's only because crashing is not considered a failure in Burnout that this sort of story can happen. The studio was also inspired by the killcam in Call of Duty games, where you get to see the person who just killed you, and can then respawn into the map and hunt them down. (In fact, a lot of Mordor's design was about trying to replicate multiplayer relatedness with computer-controlled characters). And it's not just Talion who can respawn.

Every enemy you slay has a small chance to cheat death and reappear later in the game. Perhaps with visible injures, scars, and prosthetics, which is another chance for the game to reflect the player's actions back on them. Like, for example… maybe I was being a bit hasty when I said Ar-Karo the sword breaker wouldn't be a problem. Because half an hour later, look who showed up in the middle of a fight. AR-KARO: "I should thank you.

Whatever magics you used when you took my head will not allow me to die! Getting killed by you was the best thing that ever happened to me". Gulp. Put all of this together, plus some other possible outcomes that I'll speak about later, and we can see that there's many ways for the relationship between Talion and an Orc to go forward - from humiliation to fleeing to cheating death. And so whatever way the encounter ends, every time you meet this Orc again the process repeats - but now with a memory of your previous run-ins to reference and build the story further.

Something else happens when an enemy kills you: they level up, they gain new strengths and shed old weaknesses, they get emboldened, and they often challenge a bigger orc for their position. You see, it would get boring if you just kept meeting the same Orcs again and again without any change or growth in the relationship. So the Nemesis System needs some kind of framework for these stories to grow on: and in Mordor, Monolith used one that's familiar and easily understandable to anyone who's worked in a job or, uh, been in a prison gang: the hierarchy.

In Shadow of War, every Orc exists in a top-down organisation of Overlord, a bunch of Warchiefs, the captains, and the soldiers - who are just typical, disposable NPC enemies. Though, if they kill you they have every chance of getting promoted to captain themselves. Killing Talion can make the enemy rise up through the ranks. But if you shame a Warchief, they'll get demoted back down to captain. And it's not all about Talion: Orcs are given randomly generated missions that automatically resolve after a certain amount of time and can lead to promotion, demotion, and death - causing the balance of power to organically shift as you play.

So if Talion's immortal nature lends itself to stories of vengeance, the hierarchical framework leads to different story tropes: such as fall from grace and rags to riches. Like, in my game, how Maku the humiliating Orc captain decided to finally finish the job - and use his newfound status to overthrow the overlord for top position. Which is quite the move up - that's like me getting a million subscribers and then submitting my resume to become the CEO of YouTube.

But it also means that Maku is now absolutely untouchable unless I lead a full on assault of his heavily guarded fortress. The Orcs can also have other relationships, like a captain being a bodyguard to a warchief. Or one Orc being a devoted blood brother to another. BOLG: "I won't see my blood brother slain by such a useless little tark!" And later in the game, you get a chance to make your own relationships by recruiting Orcs onto your side of the war.

So, after Maku became Overlord, I had an idea. No matter how many times I killed Ar-Karo: The Stitch, he kept coming back. This time, with a massive iron helmet holding his head together. AR-KARO "Is that surprise I see on your face? Did you really think you'd killed me? Don't make me laugh, it may tear my stitches!" And it was at this point that I realised that me and The Stitch have more in common than I first thought: we're two immortal souls, trapped in an endless battle of death and respawning.

And so if I'm going to build an army to take down Maku the humiliator, perhaps we should actually work together. AR-KARO: "I swear allegiance to you!" Now, I'll admit that the relationship between Talion and his followers isn't quite as well defined as Talion and his rivals - it is, after all, called the Nemesis System. So, a recruited captain will effectively leave the map and may have very little interaction with Talion from that point onwards.

It can be as much of an end point as the Orc's death. But there are some interesting possibilities. A recruit may decide to betray you and return to the enemy's side. You might install a spy in the enemy's ranks, only for him to be found out and executed. And a favoured follower might show up in a clutch moment to save you from certain death. AR-KARO: "Death cannot take you today! Just as it cannot take me." Thanks buddy!

Whatever the case, these different relationships help flesh out stories because they force the narrative to grow beyond simple one-on-one tales between Talion and a single Orc. Instead, it creates a weaving matrix of different relationships and dependencies that can lead to more exciting stories.

So, hopefully, you can now see why I make the link between Mordor and improv. In most video game stories, the narrative is entirely predetermined. Even those games with branching paths and multiple endings are all plotted out ahead of time - like a choose your own adventure book. The player then navigates their way through this scripted story. But in Mordor, the story evolves unpredictably - because its entirely based on your interactions with these Orcs.

It's constructed at runtime, encounter by encounter, using your interactions as narrative brickwork. Systems like cheating death and humiliation allow the stories to be longer. The hierarchy allows the cast of characters to grow and change. And relationships between the different Orcs creates a web of interlocking characters. But even though we've now got a pretty solid system that allows for stories to happen - how does Monolith make sure that those stories are actually any good?

First, it's important that you can actually remember and distinguish between these different Orcs. You'll encounter around 100 captains over the course of a game, and so it's vitally important that the player is able to keep track of their relationships with the key players. An Orc might remember you, but you don't always remember them. To make this work, the Orcs need to have really strong personalities. They need to be visually interesting and have unique traits, like the singer.

GHÛRA: "I sing this song with all my breath. Take heed! For this interlude ends with your death". Or the poet. ZUKA: "Your fate just went from bad to worse. You face an Orc, who speaks in verse". Or the obsessed. ZUKA: "I don't think I've ever seen such a beautiful corpse. This is a corpse you could love! And love. And love." These Orcs reference their unique trait constantly, to keep it memorable. So you might not remember his name, but you will remember "that guy who keeps talking about branding".

And to keep it consistent, the game defines the Orc's identity first and then makes everything else support that - such as the weapon it uses, the outfit it wears, the choices it makes in combat, and even its mannerisms - like this god damn singing Orc who constantly says… GHÛRA: "Let's siiiiing". Because while Mordor is highly systemic and makes significant use of procedural generation, there's still a lot of carefully handcrafted content in there which helps certain Orcs become highly memorable characters.

The Stitch, after all, is just a handcrafted character who may appear when an Olog cheats death. But, The Stitch could be a captain, a warchief, a spy, a follower, or any other role. There are simply hundreds of voice lines for each Orc, to account for every eventuality.

Second, the game needs to create strong, emotional connections to these Orcs. They're not just characters - they're rivals and nemeses. This connection is usually forged when you die: the kill animations are aggressive and painful. The orc insults you with taunts after your death. And we see the orc celebrating your demise and being rewarded with a promotion. They may even change their name to denote the way they murdered you.

If this isn't enough, you're encouraged to get revenge for gameplay purposes because killing an Orc who murdered you leads to way better loot. Now, these stories can be filled with really cool moments. Things like an Orc cheating death, repeatedly humiliating you, betraying your trust, or becoming a deranged, babbling weirdo. These can be really powerful bits of narrative… but only when they're rare occurrences. If it happens over and over it becomes rote, predictable, and just another gameplay mechanic.

So these events are designed to be uncommon. According to Monolith, in a typical playthrough of Shadow of War the vast majority of Orcs will never cheat death, meaning that these truly nemesis style relationships feel rare and memorable. To make this happen - well, almost everything in Mordor has a random chance to occur. If you're downed, there's an invisible die roll to see if a follower Orc will save your life. And, simply put: all of the most surprising interactions are given an incredibly low chance of ever happening.

And going further, some events, like certain transformations, can only happen once and then are locked from ever happening again in that playthrough - to ensure that those moments are truly surprising. Ideally, we want these rare occurrences to happen to the orcs we actually know and remember. So you need to know about a secret statistic that every Orc carries with them - the player interaction score, which ticks up every time you rencounter the same Orc.

The higher the PIS, the more likely that the Orc will cheat death, survive in battles with other orcs, and more. And so in play, it means that the orcs you know the best - the ones who have killed you multiple times, or have shown up again and again - are the ones most likely to stick around, and to have the key roles in the story going forward.

Of course, it wouldn't be good if an orc cheated death but spawned in some obscure part of the map and you never saw them again. So to make sure those cast members stay relevant, Monolith cheats with how Orcs spawn and will allow a key rival or nemesis to teleport in at the most inopportune moment. Orcs can even travel between the different regions in rare circumstances, so characters you had a strong relationship with in one part of the game will come back in another.

There are even more secret stats behind the scenes to help drive drama and bring balance to stories. For example, if you just kill or recruit every Orc you encounter, it's likely that your story is getting a bit one note. So design director Bob Roberts says "That's a knob we can turn. If you're doing too well, maybe somebody should piss you off and betray you and give you a revenge target to go after." Though - I'm not sure how aggressive this balancing is.

There were times when I had to manually increase the difficulty level because the game was just too easy, and my stories were becoming stagnant. And finally, Monolith knows when to step back. Ultimately, much of the narrative in Mordor takes place in the player's head, as they make connections, infer relationships, and generate histories that may not actually be there. For example, this Orc appears and says he wants to get vengeance for me killing his blood brother… STAKÛGA: "You gotta be careful in Mordor, haven't ya?

You never know who's got a big brother, keen for revenge." …but notably stops short of saying who that brother actually is. This allows me to fill in who would be the most interesting candidate for a revenge narrative. The Orcs only have short stabs of dialogue, after all - not massive plot-driving cutscenes. But these core anchors are enough for the player to fill in the blanks. It's human nature to find patterns and build narratives from disparate events, so why not just leave some of the heavy lifting to the player's brain?

So, put all of this together and you get some pretty amazing stories. Like, the random Olog who broke my sword, and got promoted to captain. Only for me to hunt him down and chop him to bits. He then came back to life as The Stitch: an unstoppable patchwork predator who just wouldn't stay dead. But with the humiliating Maku now locked up safe in his fortress, this encouraged me to recruit The Stitch into my army, and make him my bodyguard.

We want on adventures together. I healed him when he nearly died, and he saved my life when I was close to death. And when I built my army, installed my spies, stormed the fortress and finally killed Maku, you can be sure who I installed as the new leader. Ar-Karo: The Stitch. Death-defying breaker of swords. Overlord for life.

If there's one question people often ask of the Nemesis System, it's: 'why haven't we seen it in other games'? Well, for one thing, the developers at Monolith actually, and annoyingly, have a patent for the system - meaning that other studios may be scared to use a similar system and face legal action. They don't want to end up like, say, The Simpsons: Road Rage which copied Crazy Taxi's legally protected gameplay, leading to a court battle between Sega and Fox Interactive.

Mordor publisher Warner Bros., however, should be free to use the system and there have been rumours of it showing up in future Batman and Harry Potter games - but we haven't seen anything concrete yet. That being said, we have seen some Nemesis-like mechanics in other games, such as the Mercenary system in Assassin's Creed Odyssey, and the Play as Anyone mechanic in Watch Dogs: Legion. But because these systems only have a surface level take on the system - without the massive structural overhaul or the focus on making more meaningful stories emerge, these things just can't touch Mordor when it comes to generating narratives.

But one big reason for the Nemesis System losing popularity might be that while Shadow of War is an incredible next generation step in procedurally generated stories… the only thing anyone was talking about upon release was the slimy microtransactions, lootboxes, overinflated endgame, and other trappings of nauseating live service game design. The franchise's good name was tarnished, and the developer's hard work was largely ignored.

But I really hope this doesn't mean the end for the Nemesis System. As it stands, I think the system is pretty amazing. Shadow of War is a largely bog-standard open worlder with Arkham Knight's combat system glued onto it - but it's elevated to something incredibly special thanks to this system. A system that is able to make stories that are meaningful, memorable, and - most critically of all - deeply personal to every individual player.

But there's also so much room for this system to grow - and so I hope we see it developed even further in future games. Whether that's another Middle-Earth adventure with even more complex relationships with the Orcs - or something else entirely. But for now - I reckon you should give the game another shot. All of the microtransactions have been removed and if you play on Nemesis difficulty (and pretend the game ends before the enormous epilogue), I think you'll have a good time.

AR-KARO: "Now to end this. And by this I mean you!"

Hey! It's indie game recommendation time. I think we need a change of pace after all that killing. So this is Alba: A Wildlife Adventure which is an absurdly cute game about doing good deeds in a tiny open world. My favourite mechanic is the photo app, which tasks you with snapping pics of the island's many unique animals. It's an adorable and relaxing adventure, out now on Steam and Apple Arcade.