The first time I arbitrated a Necromunda campaign, I almost killed all the gangs in the first game. I had a large collection of Tyranids for Warhammer 40,000* at the time and thought how much fun it would be to challenge the players with a gribbly-filled scavenger hunt. As it turns out, the average underhiver is no match for a Lictor armed with flesh hooks, scything talons and haemotoxin. By turn 3, most of the gangers were dead or dying as three Lictors** roamed the board looking for fresh kills. The moral of the story is that cool ideas are all well and good but, if you're going to make up the rules, they need to not only be fun for you but also fair on the players.
Arbitrators are an integral part of what makes a Necromunda campaign awesome, and a key aspect of their job is to create a memorable story for the players to enjoy as their gangs battle it out. Of course, it's also the arbitrator's job to maintain balance so no-one is unduly penalised and everyone has a good time. My mistake wasn't kicking off my campaign with a monster-filled multiplayer game, but rather how I executed it. In hindsight, I probably could have saved it once I realised how outmatched the gangs were by dialling things back a bit, but back then, as a relative newbie to wargaming, I was a bit too slavish to the letter of the rules, and once the game had started we were destined to play it to the bitter end.
Another lesson learned from that first crack at running a campaign was when to use a light touch. Necromunda is a great game, with lots of depth and a ton of extra detail players can inject into their turf wars even before we venture into the territory of having an Arbitrator around. This means that sometimes a small change can be all that's needed to add some flavour or steer the game in the direction needed, while the players can get on with the rewarding process of shooting each other to pieces! In the above example, a multiplayer scavenger hunt scenario to kick off the campaign would probably have been enough, and I could have left the Lictors at home.
Fortunately for me, my mates forgave me my little "Lictor Party"* and we were able to carry on. It was certainly a good lesson in how to create a scenario that was both fun to run and fun to play. It's this kind of balance that really defines the role of a good Arbitrator, and it's worth remembering the Arbitrator is another player too - even if they're not running a gang themselves. As that first campaign went on, I got better at making homebrew games and judging the strength of the player's gangs - creating interesting mobs of crazed Cultists, soulless Spyrers and mutant renegades to challenge them. Occasionally, though, I'd still bring along a Lictor and just leave it in sight on top of my figure case, just to mess with the players...
While it might seem like the most straightforward part of a campaign (odds are you already know the people you are going to be indulging in miniature gang violence with), choosing matchups in a Turf War can sometimes benefit from a bit of planning. While turning up each week and boldly challenging someone to a gang fight might work with smaller groups, this can mean that the same players end up playing each other again and again, or even that some players miss out on games because they turned up late or missed a week. It might also mean the more confident or outspoken players are always choosing who they face - and really, everyone should have a chance to get the drop on the opposition at least once. Previous editions of Necromunda have always left these choices up to the players. However, for Arbitrators and groups looking for a bit more structure, why not try one of the methods below?
Perhaps the easiest method is to have the campaign Arbitrator organise who plays whom. But, in all likelihood, the Arbitrator is also one of the players, so to keep things clearly impartial this could be a random draw (with the exception that no player can face the same opponent twice in a row) or even a Swiss system, with the two gangs with the highest Gang Rating gangs facing off, then the next two and so on (which generally works well, as Gang Rating should be changing every week).
If the players want a bit more control over who they face then the Arbitrator could allow them to choose their opponents (once again making sure they don't choose the same opponent twice in a row), with the gang with the lowest Gang Rating choosing first, and working their way up through the Gang Ratings until every player has an opponent.
A round robin (where each gang fights each other gang once over the course of a campaign round) is another option. This method works best in smaller campaigns, as it can be difficult to organise if there are lots of players, some can't make it every week and subsequently drop out, or if new players join the campaign. Of course, this method does have the advantage of everyone getting to play everyone else, so by the end of the campaign, all the gangs will have faced off against each other at least once.
Whatever method is used, the Arbitrator can speed things up by arranging games before the players meet up - this means that two players, once matched up, can play their game when they are both free, or if a player unexpectedly drops out, their opponent can be assigned to another player before everyone gets together.
In this post I'm going to get into what is perhaps the most important and rewarding aspect of running a Necromunda campaign - I am of course talking about spinning a good yarn.*
But how do you turn your campaign into a good story? Well the good news is a lot of that will take care of itself and players will fondly remember the time their opponent's bomb rat scurried back to its owner before turning them into a mushroom cloud of meat and organs, or that time they had the enemy dead to rights and their stubcannon clicked on an empty chamber. The rest, however, can be helped along by the Arbitrator and players.
As grudges develop between different gangs, the Arbitrator can adjust the campaign to match. Rival gangs should be given the chance to settle their debts - if one gang hits an enemy in an Ambush scenario, maybe the players play out the revenge with the wronged gang performing a Sabotage on the ambusher's turf. Likewise, if one gang has been giving everyone else a kicking, maybe it's time for a multiplayer game as their enemies team up to take out the hated foe, with the defending gang getting to set up the board and make their rivals pay in blood if they think they're hard enough.
Scenarios are fertile ground when it comes to creating a good story. As the gangs grow in strength and enemies are made and creds are earned, the Arbitrator can throw in some of the more unusual scenarios to shake things up. The Pitfight scenario from Gang War 3 is a great leveller as gangs can only field a single fighter, while Escape the Pit! from the same expansion favours the fleet of foot over the heavily armed. If something in the campaign suggests a scenario, players are encouraged to play it out.
If two gangs want to make an alliance against their enemies, then play a Gang Moot from Gang War 3 to give the other players a chance to spoil the deal. If a gang has been targeted by the Guilders, then play the Last Stand (also from Gang War 3) and give the weakest gangs a chance to make some creds taking them out. Or maybe the gangs have conquered the local sector and are lording it over a large settlement - consider the Settlement Attack from Gang War 4, with the gangs having to band together to see off a massive mutant horde assembled by the Arbitrator!
When it comes to creating a good story the rule of thumb should always be - does this seem like a move my gang Leader would make? And if the answer is yes, then go for it! Players should be encouraged to develop personalities for their Leaders and make decisions based on their quirks. Maybe a Van Saar Leader is a driven technophile, and is obsessed with hunting down a gang with an Ambot - or attempting to find one of their own - or perhaps their go-to mission is Archeo Hunters. Alternatively, a Goliath Leader might want to prove he is the hardest fighter in the underhive and is on a personal mission to single-handedly take out each opposing Leader in close combat.
As the Arbitrator you can reward this kind of behaviour by giving players bonuses (such as creds and weapons from the Guilders or extra rolls on the House Favours table) if they manage to complete them.
Perhaps the key thing to remember as an Arbitrator when forging a narrative in your Necromunda campaign is to listen to your players. If a player wants to do something cool like raid a Guilder caravan or offer a bounty for an opposing gang's Leader then consider working it into the campaign - odds are the resulting scenario will be memorable, not to mention fun for all involved!
So your Necromunda campaign has been a great success and has rumbled on for a few weeks. The fortunes of the gangs have risen and fallen as they tear each other apart in bloody gang violence. But now a new player has turned up and wants to jump in - what's the best way to introduce them to the game?
While on paper it's easy for a new player to join an existing campaign - they simply write up a fresh gang and look for a game - new players can be at a bit of a disadvantage, especially if they are facing off against a bunch of hardened outlaws with much higher Gang Ratings. Arbitrators are faced with two issues - do you give the new player bonus credits or gear, even though this might seem unfair to the gangs who have earned these the hard way? Or do you let the newly minted gang fare for itself through some lopsided games?
This can be even more troublesome when you consider that the gangs in the campaign might have a variety of Gang Ratings, with some not much higher than their starting level.
To find the answer for this one, consider what is going to be the most fun for the people involved - Necromunda is, after all, a game, and games are fun!* If the new player is content to start at the bottom - and the bulk of their opponents are not more than a few hundred creds higher than them in Gang Rating - then grant them their wish! The advantage of this method is it gives the new player a sense of accomplishment if they survive, knowing they have faced the worst the underhive has to offer and come out the other side.
If the majority of the players have Gang Ratings more than 500 credits higher than the starting player, it might be worth giving them a small bonus. The easiest way to do this is to either give them some extra creds (perhaps equal to half the difference between their Gang Rating and the next lowest player's gang) which must be spent on items from the gang's House Equipment List, or allow them a couple of extra rolls on the House Favours table from Gang War 3.
Another option is to give everyone a bonus - or the 'stick made out of carrots' approach, as it is known.** There are a couple of ways to do this. One of the most fun is to have a multiplayer game to introduce the new gang to the neighbourhood. The Gang Moot scenario from Gang War 3 is a good choice. The new gang gets a chance to earn some creds and get some experience without having to take on the strongest gangs alone - while all the gangs who take part get some rewards.
Alternatively, the Arbitrator might allow the new gang to choose some lucrative scenarios for their first games, or give them extra bonuses (whether they win or lose), giving them the chance to close the gap with the stronger gangs.
Whichever method is used, the key is making sure new gangs are given a chance to shine, and new players feel like they are making a difference in the campaign rather than just standing on the sidelines as the most powerful gangs slug it out for supremacy.
The year was 1997, the place: my mate's garage in one of the inner suburbs of Newcastle.* We had been playing a Necromunda campaign for a few weeks and my Delaque gang, the Snake Charmers, had been taking a beating at the hands of the other gangs, but I had a plan...
Proposing a parlay in the settlement of Two Tunnels (one way in, one way out), Joe Twice-Bit, Leader of the Charmers, convinced the other gang Leaders to meet him alone while everyone's Gangers took in the delights of the local drinking hole. Little did the other gangs know, Joe had made a deal with the devilish Karloth Valois** and Two Tunnels was about to face its own personal zombie apocalypse!
The game described above stands out in my memory because of the story we created that night, but also because it was only possible due to the creativity and open-mindedness of our Arbitrator. We had chatted a few days before the game about how I might turn the fortunes of my gang around. He had some suggestions about various homebrew scenarios he had made, and how he wanted to run a game where all the gangs fought off a zombie attack. This sparked an idea of my own, maybe my Leader could manipulate the situation to his own advantage... and so a plot was hatched.
One of the reasons my mate wanted to run a game with lots of plague zombies was because he had a Warhammer Vampire Counts* army and as a result lots and lots of Zombies! Over the years I've played many scenarios like this based on the models I've had in my collection - in fact, earlier this year we put together a Necromunda game for the Horus Heresy and Necromunda Weekender involving a gigantic spider largely because I found an Arachnarok in one of my desk draws!
Perhaps the most fun aspect of my mate's homebrew scenario, which saw our gang Leaders starting in a room surrounded by zombies while our Gangers were staggering around looking for their guns, was that while I thought I was setting a trap for the other gangs, they had plans of their own. While I'd had a chat with my mate before the game, so had some of the other players. The result was guns stashed beneath tables, Ratskin allies turning up to help out and even a minefield laid on the only road out of town.
While I'm not sure the Snake Charmers came out of Zombie Night in Two Tunnels better off, everyone had a lot of fun, and of all the many Necromunda games I've played, I still remember it fondly...
* Newcastle, New South Wales as opposed to one of the other ones.
** A classic Necromunda character, psychic space vampire, zombie master and contender for the 'Most Pointy Collar' award.
*** Now known as Soulblight, for the most part.
One of the Arbitrator's jobs is keeping the players apprised of the progress of the campaign. At its most basic this can mean sending out emails or maintaining message groups that provide information on changing Gang Ratings, meetup times and things like game pairings or the introduction of new players. Of course, this weekly round of updates can be much, much more... it could be a campaign newsletter!
Creating a newsletter can be a lot of fun. It is also one of the best ways for the Arbitrator to communicate their story and setting to the players. Take, for instance, the Greywater Gazette - Greywater's premier (and incidentally only) local newsrag. This was the means I used to communicate with the players when I ran my Guns of Greywater Necromunda campaign many years ago. At first the Gazette, and its editor Inky Pete, concerned itself with reporting the current gang rankings and foreshadowing campaign events - like an impending mutie migration or the implementation of a Guilder bullet tax - but as it progressed it became a platform not just for me but for the players to air their own inter-gang grievances, challenges and plots.
Between gatherings I let the players send me anything they wanted to see printed in the Gazette - with pride of place going to the best advertisements and challenges. If a player issued an especially noteworthy addition to the newsletter - such as calling an enemy out in style using lots of evocative trash talk - then I'd give them a bonus in the game if they could make good on their threats to represent the people of Greywater being suitably impressed with them. Likewise, if their opponent failed to meet the challenge, good old Inky Pete would make sure they got a scathing dressing down in the next issue and maybe even some of the local traders would refuse to sell to them (the underhive is especially hard on cowards).
Sometimes players would even submit their own version of events after playing a game. This was lots of fun and really added to the story we were creating with our campaign - especially when a gang's crushing defeat was rebranded as a wise tactical retreat or ploy to steal the enemy's bullets by catching them with their torsos...
Another great use for newsletters is for the seeding of clues and campaign events. In the Greywater campaign, the local Guilder family turned out to be Nurgle worshippers and were hatching a plot to unleash a virulent plague on the whole settlement. Right from the start, I was hinting at this in the Gazette with zombie sightings, Ratskin prophecies about the 'Time of Badwater' and even strange little symbols scrawled in the corners of the Gazette's newsheets (doubtless a means of the corrupted Guilders to communicate with their followers). During one week the Gazette had an influx of very reasonably priced Hired Guns for the gangs to recruit... the players who had been playing attention wisely choosing not to hire them, and those who did - got more than they bargained for. In the end, some gangs, infected by the Guilders, decided to side with them and we played a multiplayer game with the Chaos worshippers versus the remaining gangs for the fate of Greywater - and, of course, Inky Pete reported it all in the Gazette!
Necromunda is a detailed wargame that offers players lots of choices - both when it comes to building forces and playing games. Players are presented with myriad options for their fighters, from skill and characteristic combinations to a vast array of weapons and wargear with which to arm them. For the Arbitrator, Necromunda offers even more options, with dozens of different scenarios, rules for running different kinds of campaigns and lots of additional content like campaign events and special territories.
Presented with so much choice, it can sometimes be challenging for an Arbitrator to pick and choose which campaigns, scenarios or additional rules to use, and what options to allow their players to have access to. Fortunately though, choice is a good thing!
The first step for the Arbitrator to decide is which gangs to include in their campaign. Unless you have a good reason, there is no need to limit this - after all, if a player has been feverishly building that Genestealer Cult then they should be able to run it.
Of course, sometimes the Arbitrator might like to run a particular kind of campaign, and some gangs - like Chaos Cultists - may not fit the theme. Equally, the Arbitrator could run an entire campaign around a Chaos uprising and have some of the players specifically bring along Chaos Cultists (or at least declare their House gangs are going to be aligned with Chaos*).
The players' choice of gangs can also influence the campaign and offer the Arbitrator narrative opportunities. For instance, if the majority of players are using Orlock gangs, maybe the campaign is centred on a disputed area of House Orlock territory and the other Houses are moving in while the House of Iron attempts to hold them off.
Different kinds of games can lend themselves to different rules and rule restrictions. If the Arbitrator decides they want to run a low-tech game, or one way out in the badzones, gangs might be poorer or have to scavenge for even the most basic resources. In this kind of game, heavy weapons or weapons and wargear with a high cost or rarity might be restricted, forcing the gangs to settle their differences with autoguns and stubbers rather than melta guns and heavy bolters.
In an outland campaign, the Arbitrator might even have some effects from the Campaign Events table (from Gang War 3) permanently in effect, such as the Sump Stalker, Scum Migration and Generatorium Failure events, reflecting the perils of the outlands.
In addition to using the large selection supplemental rules presented in the Gang War books, Arbitrators can even introduce their own house rules to their campaigns. For example, for shorter, more brutal campaigns the Arbitrator could make the Lasting Injuries table more lethal. Perhaps all results are either a permanent injury or death, meaning being taken Out of Action always has a serious consequence.
Equally, the Arbitrator might want to increase the amount of Reputation or Turf in the campaign and double all such scenario rewards - or even grant Turf rewards for winning any scenario. With all of these tweaks the idea should always be to promote the kind of things the Arbitrator wants to see, whether it is giving gangs access to more toys by dishing out more creds, or making the game more or less lethal by making the rules for Lasting Injuries, Docs and Recovery either harsher or more friendly respectively.
Whatever changes the Arbitrator chooses to make, when creating house rules the players should always be asking themselves "does it make the game better?" and, most of all, "does it make it more fun for the players?".
* A perfect opportunity for players to convert up a few House fighters with unpleasant afflictions.
When we play games with our friends, especially wargames, we accept a sort of social contract with each other that our games will be fair, and hopefully also fun. After all, wargames, even amongst friends, are still competitive affairs with each of the players striving for victory - or at very least an honourable defeat in which they take copious amounts of their opponent's army with them to the grave. Sometimes though, this competitiveness can make winning seem more important than having fun or give the impression that the only way to have fun is to win. While most wargames rely solely upon the players to strike this balance between fun and fair, in Necromunda we have the Arbitrator.
Games of Necromunda, especially if they're played as part of a campaign, are seldom completely fair. This is because, depending on the scenario (who deploys where, how many fighters start on the board or how many they are allowed to field) or the relative sizes and strengths of the gangs, one side or the other probably has a slight advantage.
Of course, Necromunda also has lots of balancing factors - for instance, a gang can 'lose' a battle with another gang but still come out on top if they generate more income in the post-battle sequence, or perhaps all their Out of Action fighters recover without a scratch, while their opponent's wounded are rewarded with a trip to the doc or the morgue.*
Even so, sometimes a very powerful gang will face off against a very weak one with the outcome largely decided before the first dice are rolled. In these cases, the Arbitrator can step in to balance the scales.
When making match-ups more even, the Arbitrator shouldn't just be thinking about making the game fair. After all, a player with a large and powerful gang has probably walked a long and bloody road littered with the bodies of their rivals to get where they are, and they should be allowed to use that power without always having the number of fighters they can field, or the weapons they can bring, being restricted.
Equally, if a weaker gang is constantly getting artificial bonuses, such as access to loaned heavy weapons, free Bounty Hunters or large cred payouts it can make them feel like they are not earning their victories. Part of the fun of a Necromunda campaign is growing a gang from scratch and seeing them develop, not to mention you want your own named gangers getting the glory and not Floyd** the Hive Scum, aka Mr Kill-stealer. So what can the Arbitrator do to remedy these potential issues?
At its heart, a good Necromunda campaign is a good story - and this should always be the touchstone for the Arbitrator when it comes to making sure the players are having both fun and fair games. Imposing a scenario on players to balance out the fact one gang is far more powerful than the others becomes a lot more interesting when it is not just a collection of artificial restriction and bonuses, but maybe a plot by allied Houses to stop the rising influence of their rivals.
For instance, I once played a campaign where our Cawdor player (and his gang the Brotherhood of the Soiled Hood) had some runaway successes early on and rapidly began outmatching the rest of us. Rather than penalise them or grant the other players random bonuses, our Arbitrator decided that House Cawdor was pleased with the Brotherhood's success and granted them some more heavy weapons and some Redemptionist allies to carry on the good work. He also made them the focus of that part of the campaign, and the main 'bad guys'. This meant some gangs allied with the Brotherhood while others, my own Delaque Snake Charmers among them, formed a resistance to this Cawdor takeover.
The result was some fun multiplayer scenarios where we tried to gang up on the Brotherhood, plus some side battles and allegiance changing as weaker gangs fought proxy wars for the big boys or made their own clandestine deals. In the end, the Brotherhood was torn down by the rise of other powerful gangs, but it was the story that stayed with us. Ultimately it gave us a reason to make our games both fair (pitting multiple weaker gangs against more powerful ones) and fun (a common foe gave us all something to bond over, while the Brotherhood got to see if it could beat us all at once).
* I say morgue but I really mean corpse-starch factory. ** Not his real name.
One of the most enjoyable elements of being an Arbitrator is creating adversaries for the players to tangle with. And when it comes to Necromunda there are plenty to choose from. These can range from Bounty Hunters and Hive Scum for the gangs to hire (or to join their enemies) to full-fledged gangs, either drawn from the Clan Houses or pretty much any organisation on Necromunda.* The great thing about these Arbitrator-controlled gangs is they can be built for a specific purpose, such as assassinating a rival Leader in The Hit, defending a caravan in Caravan Heist or as a gang of desperados to face off against in a Shootout. The good news for the Arbitrator is that the Necromunda rules provide all the tools they need to build weird and wonderful gangs!
A great way to add some colour to your Necromunda campaigns is to create a collection of Bounty Hunters and Hive Scum using the rules first published in Gang War 2. Rather than allowing players to build their own Hired Guns when they recruit a Bounty Hunter or Hive Scum, the Arbitrator can make a pool for the gangs to choose from.
These desperados then create their own stories as they hire out to different gangs, pursue their own agendas and maybe even team up to form Venator Bands to work for (or against!) the interests of the Guild. The Arbitrator can also allow players to take on these pre-made Hired Guns without paying their hiring fee (making them more attractive options over regular gang members), or have them turn up to 'help' during specific scenarios to ensure they are always part of the action.
As well as building Hired Guns, the Arbitrator can create complete gangs. Often these will be Guilder Watchmen or agents in the employ of a rival Clan House. They will either be the antagonists in a scenario, such as defending or attacking a settlement defended by multiple gangs in the Settlement Attack scenario, or to complicate matters, like lawmen showing up to keep the peace as two gangs shoot it out in the Downtown Dust-up scenario.
Gangs can be created using any of the gang lists, including the Cult and Venator gangs, and built to purpose (i.e. with skills and equipment chosen to reflect their talents, such as giving a dual plasma pistol-wielding desperado the Gunfighter and Fast Shot skills). Like Hired Guns these gangs can take a memorable place in the campaign, like the outlawed Van Saar gang and their stolen House tech that requires an alliance of gangs to take down, or Hagan the bitter old watch-leader and his watchmen, who just want the gangs to quit shooting up Two Tunnels for one Emperor-cursed night!**
More detailed guidelines for creating Watchmen gangs can be found in Gang War 3.
As massive and diverse a place as Necromunda is, it is also part of the Warhammer 40,000 universe, which is even larger still. In fact, many of the institutions of the Imperium exist in some part on Necromunda, like the Temple of the Emperor Deified in Hive Temenos controlled by the Ecclesiarchy, or the Stranger's Spire in Hive Primus for visiting xenos or abhumans, like Eldar traders or Squat mercenaries. You can be sure, given all the corruption in the underhive, there's the odd Inquisitorial agent wandering about getting into trouble as well. While many of these agencies and their warriors are beyond the purview of the core game of Necromunda (which really is all about gang warfare) there's no reason Arbitrators with extensive collections of Warhammer 40,000 Citadel miniatures can't slip them into their games.
Less is usually more when it comes to tapping into the wider universe, but games involving rogue Death Cult Assassins, cruel witch hunters or Ministorum missionaries come to cleanse the underhive are all possible. And the best thing of all is both Necromunda and Warhammer 40,000 share the same gaming foundation, so converting these unusual characters to work in a Necromunda campaign is not too difficult. Just be careful with the Lictors***...
* And beyond... ** Sadly for Hagan, we never gave him a night off... *** See Arbitrator's Guidebook Part 1
Last time we talked about making custom Hired Guns and gangs - this time we will be looking at the gribblies.* Monsters are a big part of Necromunda and for those who live among the Badzones just another daily inconvenience. It is well known among hivers that as oppressive and horrible as the hive city is, at least it's not overrun by flesh-eating centipedes with flamers for eyes - unlike the underhive...
When creating a monster, the first step is deciding what role it will be taking in the game. Will it be a single lumbering behemoth like the monster in Beast Hunt that requires multiple gangs to take it down? Will it be a swarm of lesser creatures like the Carrion Hunters from Fighter Down? Or will it be a single powerful but mobile creation like the cyborg from the Murder Cyborg scenario? Large monsters, with a high Toughness, lots of Wounds and skills like True Grit or Unstoppable to keep them going serve best as distractions for gangs to avoid as they scavenge the battlefield or when there are multiple gangs able to mass their firepower. Equally, stealthy assassin creatures can be built to be a match for an entire gang, making for a fun game of cat and mouse as groups of gangers hunt the thing in the dark, no doubt secretly hoping their comrades find it first and give the pre-arranged signal.**
When making an Injury roll for this fighter, roll one less Injury dice (for example, a Damage 2 weapon would roll one dice). Against attacks with Damage 1, roll two dice - the player controlling the fighter with True Grit can then choose one dice to discard before the effects of the other are resolved.
Before making a Recovery check for this fighter in the End phase, roll a D6. If the result is 4 or more, one Flesh Wound they have suffered previously is discarded. If they do not have any Flesh Wounds, and the result is a 4 or more, roll one additional dice for the Recovery check and choose one to discard.
The best time to use an unholy creation is in a specific scenario. By making the creature central to the scenario it both ensures that all the hard work the Arbitrator has put into collecting, converting and painting their newest horror, not to mention creating rules for it, will pay off - it also means that players get the fun experience of pitting their gangs against something unusual.
There really is no limit on the kinds of scenarios the Arbitrator can create or adapt when fielding monsters - Gang War 3 and Gang War 4 include multiple scenarios and guidelines for just these kinds of games. Sometimes, the kind of campaign might suggest the monsters - for example, if the campaign involves exploring seaside sump settlements*** swarms of albino sump spiders might be an issue. Alternatively, a campaign filled with Chaos Cults might include a multiplayer game which starts with a member of each Chaos gang being spontaneously turned into Chaos Spawn... after which the action kind of takes care of itself.
Like the Hired Guns and gangs from last time, the Arbitrator can look beyond the confines of Necromunda and out into the greater Imperium if they want. Many of the monstrous creatures found in the Warhammer 40,000 Citadel miniatures range can be adapted for Necromunda, either because they are things that have fallen from the sky - maybe by stowing away on transports or sometimes just literally falling from the sky - or you might choose to represent Necromunda's homegrown horrors with appropriate models from other Citadel ranges.
The Arbitrator does need to be careful with some of the more outlandish beasts, though - Necromunda gangs are talented and violent criminals but may lack the training (and heavily armoured support) of the Astra Militarum when dealing with a Carnifex. Lone xenos - a Genestealer (just the one!), an Ur-Ghul, some Kroot mercenaries or a Clawed Fiend - can make for an interesting confrontation between the scum of the universe and the scum of Necromunda...
* The gribbiliest gribblies that ever gribbled. ** Typically a long, piteous scream followed by complete silence. *** A.K.A. the worst beach holiday ever.