I run a fantasy Genesys game set in the Magic The Gathering multiverse. My group tends to avoid direct conflict, which is why I was really surprised that during peace negotiations one of the PCs shapeshifted into a dragon and tried to eat the general they were meeting with! I ran a hastily thrown together combat verses the general and his elite entourage and the PCs won, but during the combat several antagonists were "punted" out of the tent they were meeting in by the treant and eventually the tent was outright destroyed. Since they had been meeting in the middle of the enemy army, I ended the session by describing how the entire enemy army is turning to look at them and starting to draw weapons. To my surprise, instead of hearing my players talk about how they were going to try and escape this difficult situation, they were instead talking about how excited they were to try and fight any army. This leads me to my issue: how do I stat out an army? I thought about doing numerous minion groups ... but to represent that many soldiers would be a LOT of minion groups. I have found some mass combat rules that people have posed online, but they all seem to rely around the PCs leading an army of their own, not just trying to single-handedly fight an army. I want to give my players a challenge that represents the enormity of what they are trying to accomplish, but that is also overcomable (if only theoretically). Does anyone have any ideas on how I should handle this?

I would set it up using a form of enemies come in waves. An entire army is going to take time to get the news then get armed to fight. As this could potentially be deadly for the PC's I would also look at settting up a "round" limit or the PC's are overrun by this horde of armed soldiers. If they are sufficiently powerful then disregard the second bit.

The simplest, roughest hack to facilitate this would be to treat each minion in a five minion group as more than one soldier. With each minion counting as ten people you could pit your players against a hundred soldiers by running mere two minion groups.

Obviously, this'll let the PCs cut through the amount of people that would likely destroy them if handled according to the rules, so you may want to compensate by buffing the minions.

The first thing that comes to my mind is swarms. A swarm is a rival adversary that represents dozens or even hundreds (in the case of insects) of individuals. Just create a normal rival and give it the swarm ability (Halve the damage dealt to this adversary before applying soak, unless the attack has the Blast or Burn quality [regardless of whether the quality is activated]).

You could pretty easily have a silhouette 2 or 3 Squad of Pikeman (Rival) that represents 16 people. WT of 20 and soak of, say, 4 and you're halfway there. Two of those squads is over 30 individuals, but it's only two initiative slots and only two "units" for the GM to worry about!

If you do go the silhouette 3 route, I'd give them an ability that gives them a boon when attacking a silhouette 1 target, otherwise they'll end up increasing the difficulty of their check.

The Phalanx rules from Rise of the Separatists in the Star Wars line would work quite nicely in this situation.

I was also interested in the topic of representing PCs fighting huge amounts of enemies. There was a Warhammer 40K RPG game published by FFG called Deathwatch and it had a special mechanic for that. In Deathwatch you play as a Space Marine (a genetically modified supersoldier). One of the things the designers of the game wanted to represent is overcoming giant hordes of relatively weak enemies (imagine 5 guys surrounded by a sea of orks). So, they created a concept of a Horde. Hordes don't include a specific amount of enemies, instead they have magnitude, an abstract value that represents their size. I tried to adapt that mechanic to Genesys and come up with the following.

Minion horde is a special type of minion group. A minion horde (or simply horde) represents a group of so many minions, that counting individual enemies is no longer practical. Instead, a horde's size is represented by its magnitude. A horde increases its silhouette by 1. For every 30 units of magnitude the silhouette is further increased by 1 (e.g. magnitude 60 horde of horses is 2 + 1 + 2 = 5). For the purposes of skill checks a horde counts as a minion group of size 6 (i.e. having rank 5 in skills).

When attacking a horde, these rules apply:

• A horde doesn't suffer wounds as a regular minion group, instead each hit that inflicts wounds reduces the horde's magnitude by 1.
• Any critical injury additionally reduces the magnitude by 1.
• Planetary scale weapons reduce the magnitude by 1 for each point of damage inflicted.
• Activating Auto-fire quality does not increase the difficulty of the check (there are so many enemies that it's hard to miss). Note that this makes automatic weapons much more preferrable when fighting hordes than single shot weapons with high damage value, as a single attack may result in multiple hits.
• Activating Blast quality results in a number of additional hits equal to the quality's raiting.
• Successfull attacks with Breach quality generate a number of additional hits equal to the quality's rating (this represents the weapon shooting through several enemies in a line).
• Additional hits from Auto-fire, Blast and Breach should all be allocated on the same horde.
• Melee weapons count as having Auto-fire quality.
• Any action or effect that grapples, disorients, staggers etc. instead reduces the horde's magnitude by 1.
• As a minion group, a horde can't voluntarily suffer strain. If some other effects inflict strain on a horde it reduces its magnitude once per turn.

When a horde attacks these rules apply:

• Depending on its silhouette a horde can span several range bands and engage multiple characters that aren't engaged with each other.
• A horde can act as a minion group. However, instead of the standard Perform a Combat Check action a horde can use the special Perform Horde Combat Checks action. As per that action, the horde can perform a melee attack for every engaged enemy character and a number of range attacks equal to its magnitude divided by 10 rounded down.
• When making ranged combat checks a horde counts characters it is engaged with as being at short range (we assume, that those members of the horde that are further away are shooting). However, it counts those characters as engaged with an ally (the horde itself), and thus upgrades the difficulty of the check and hits itself if a Despair is rolled.

As mentioned above, these rules keep a necessary damage threshold, so you can't use a BB gun to fight an army, but very clearly favour automatic fire,
explosives and artillery. On the other hand they still allow for epic melee slaughters.

By the way, note how a horde of magnitude 30+ that consists of humanoids has silhouette 3+, which means that shooting at it at short or engaged range has Simple difficulty.

What's missing is the topic of wiping out a horde. If the PCs are successfull at slaying their enemies, the horde might break (there is an encoded rule for this in Deathwatch, but I thought that this should be dealt with more narratively in Genesys). If the horde keeps its ranks and its magnitude is reduced below a certain value, you might want to replace it with several minion groups (e.g. at magnitude 10 replace the horde with several minion groups each
engaged with a PC).