Mercenary II: Mass Combat

In the last playtest preview, we showed you how to put your recruits together into a cohesive force – now we show you how to get them fighting!


Battles using the mass combat system use exactly the same rules presented for combat in the Traveller Core Rulebook, with just a few changes. These changes are listed below but, whenever in doubt, the Golden Rule is always assume that the standard combat rules from the Traveller Core Rulebook are used as normal. This will allow you to use rules from any Traveller book with no conversion or adaptation necessary at all.



In mass combat, Dexterity is not a factor for determining Initiative. Each unit must instead make a Tactics (military) check, with Intelligence used as a modifier. This is made by the leader of the unit.


The Combat Round

A combat round in mass combat usually lasts for six seconds of game time, just as it does when it involves characters. This is increased to a minute if units of greater than Size 1,000 are present, and an hour if units of greater than Size 10,000 are present.


Minor Actions

As with characters, units can perform one minor action in every round (or two if they forgo their significant action), allowing them to move, change stance, draw/reload and aim as normal.

However, movement is increased to 50 metres if the rounds are a minute in length and 2,500 metres if the rounds are an hour in length.


Significant Actions

Again, the significant actions available to units are the same as those for characters.


Miscellaneous Actions

For both minor and significant actions, miscellaneous tasks are effectively unlimited for units, as a unit has many members that can be delegated to perform them. However, while a unit may perform many miscellaneous actions in a single turn, only one miscellaneous action of any one type may be performed in that turn.

For example, a unit may have someone make a Leadership check to issue specific orders to another member, one member use a psychic power, while yet another tried to break through the security systems to open a bunker door they are all attacking. However, the unit could not have two members make Leadership checks to issue orders to the same individual (they would likely contradict each other and the individual may not know who to listen to – or worse, would choose who they want to listen to…).

Any individual of a unit not actively engaging in the unit’s own action will instead act as though they were an individual character for that round, using the normal rules in the Traveller Core Rulebook.



Units may make reactions just like characters. Dodging, for example, represents a unit taking best advantage of the terrain around it in order to avoid taking incoming fire. It also represents the effects of suppressing fire upon a unit forced to take multiple dodging reactions in a turn.



Attacks are performed by units in the same way as for characters, using all the common modifiers to attack listed on page XX of the Traveller Core Rulebook, including the use of environmental conditions, cover, and automatic weapons. Range bands are also used as normal.


A unit takes damage to its Endurance score. When this reaches 0, the unit has ceased to function as a fighting unit. Its individual members are assumed to have been killed, seriously injured or disbanded, scattering themselves in an effort to leave the battlefield. The unit will take no further part in the battle and is effectively destroyed, though it may be possible to recover some of the individuals and rebuild the unit (see page XX).



When one unit is much larger than the enemy unit it is fighting, it will outmatch its enemy. The unit it is fighting will be outmatched.

This has an effect on both attack rolls and damage dealt, and is based on the unit’s Size. If a unit is at half the Size or less of its enemy, it will be outmatched. If it is at least twice the Size of its enemy, it will outmatch the target. In either case, the table below is consulted for modifiers to both attack rolls and damage.

Unit Size is… Attack DM Damage
At least ten times the size of the enemy or more +5 x10
At least five times the size of the enemy +3 x5
At least three times the size of the enemy +2 x3
At least twice the size of the enemy +1 x2
No more than 50% the size of the enemy -1 x1
No more than 33% the size of the enemy -2 x1
No more than 20% the size of the enemy -3 x1
No more than 10% the size of the enemy -5

Damage is further multiplied by the overall Size of the attacking unit. Larger units are able to carry a lot more guns and unleash a truly awesome amount of firepower. Damage is therefore modified by unit Size as shown on the table below.

Unit Size of Attacker Damage
10 or less -5
11-20 -3
21-50 +0
51-100 x2
101-250 x3
251 or more x4



Even the most disciplined and battle-hardened troops have their limits. When great adversity rears its head, be it through starvation, lack of ammunition or watching half one’s own unit get massacred, troops can lose the will to fight, becoming less effective in battle or even breaking into a full blown rout.

This is handled by the Morale score of a unit.

A Morale check is made the same way as a characteristic check, rolling two dice and applying the unit’s Morale modifier. Morale checks are necessary whenever one of the situations below arises. Referees can, of course, call for a Morale check in other circumstances as they see fit.

Situation Morale check Difficulty
Unit Endurance reduced to half of original score Average (+0)
Unit Endurance reduced to quarter of original score Difficult (-2)
Unit Endurance reduced to one third of current score in a single round Very Difficult (-4)
Unit suffers more damage in a round than enemy during close combat Average (+0)
Unit suffers damage from an enemy unit of three times or greater Size Difficult (-2)

Morale checks can also be subject to further modifiers, depending on the specific circumstances in which they are taken.  Some suggestions are shown on the table below but, once again, referees can change these modifiers or impose new ones dependant on the mission being undertaken and the actions of the players.

Situation Morale Modifier
Unit in a strong defensive position +4
Unit not paid last month -1
Unit not paid for last three months -4
Unit won last battle +1
Unit on the winning side in the campaign +1
Unit lost last battle -2
Unit on the losing side in the campaign -4
Unit not eaten in the past day -2


Recovering Casualties

The Endurance of a unit does not specifically track deaths of individual members though, after a heavy battle, there are likely to be plenty of those. As mentioned earlier, a unit’s Endurance is a representation of its ability to continue fighting through individual death, injury, surrender and cowardice.

At the end of every battle, a percentage of lost Endurance points can be recovered as those who were injured receive medical care and those who ran come out of hiding.

Roll 2D for each unit, modified as shown on the table below. Then compare the total on the next table which will show you the percentage of Endurance points that can be recovered.

Unit… Recovery modifier
Was reduced to 0 Endurance -4
Was reduced to at least 25% of its starting Endurance -2
Was reduced to at least 50% of its starting Endurance -1
Was reduced to at least 75% of its starting Endurance +2
Was reduced to 0 Endurance in close combat -6
Has at least one Medic for every 10 individuals + double Medic skill
Has at least one Medic for every 30 individuals +Medic skill
Has at least one Medic for every 100 individuals + ½ Medic skill


2D Endurance Recovered
1 or less None
2 10%
3 25%
4-5 33%
6-8 50%
9 66%
10 75%
11 90%
12 or more All


Characters Within Mass Combat

Generally speaking, the players’ own characters should be kept apart from mass combat – have the players make the rolls for the units under their command, by all means, but their actual characters should have a chance to perform heroics and necessary tasks beyond the skills and daring of the men and women they are leading.

The length of the round in most mass combats is the same as a combat round for characters (six seconds), so anything a character could attempt to do in a round of combat is equally applicable during a round of mass combat.

If a player’s character is within a unit engaged in mass combat, he should always have the chance to act independently, on his own initiative order (giving him every chance to act before his own unit, and thus perform some truly heroic/stupid actions).


Engaging Units

Individual characters may not engage units as such, but will instead attack individual members of the unit. This is done using the normal combat rules presented in the Traveller Core Rulebook. Every casualty they cause in an attack will reduce the unit’s Endurance by 1.



The characters of players are effectively immune to morale, with the players themselves making the choice of whether to fight on or surrender (though units trying to surrender may take a dim view of characters continuing to fight and thus provoking the enemy). Indeed, many actions by characters can have a direct influence on how the unit they are within or near will fight.

The table below lists a few options players may try to boost (or not) the morale of nearby units, though the referee is always welcome to add more as the need arises – all else being equal, a player should always be rewarded for bravery and earn the respect of the unit. The DM earned by the player is applied to the next Morale check the unit is called upon to make, though the referee may extend this to several checks if the action was particularly noteworthy.

Player’s Action Morale DM to Unit
Single-handedly killing an enemy leader +2
Single-handedly killing a minor officer or sergeant +1
Destroying an enemy vehicle +1
Destroying an enemy armoured vehicle +2
Fleeing the battle or hiding in fear -4
Reducing an enemy unit’s Endurance by at least 10% with one attack +1


The mass combat rules presented in this chapter handle battles between two forces simply and easily. Even when two entire armies are fighting one another, each is assumed to be acting as a single unit, even though both might have separate companies, air units, artillery and specialised troops. It is assumed all such components are acting together in the best fashion they can to achieve the combat results that are rolled for each round.

However, at some point, both players and referee are going to want to add a bit more detail to their battles. The players might want to detach a company from their main force, for example, and send it on a wide-flanking manoeuvre to make a direct strike on an enemy artillery position, thus making things easier for the rest of their army. They may want an armoured unit to take position in a thick forest and lay low, hidden as they wait to launch an ambush. Perhaps they issue orders for a company to split with its three platoons each assaulting a different section of trench lines.

This is when a mass combat using multiple units is desirable, with the players giving orders to each unit as they respond to the actions of units under the control of the referee. There are two ways to handle this.


Map-Based Battles

The immediate response of some referees will be to grab a few sheets of graph paper and start plotting out terrain and unit positions – and this is perfectly valid. Every unit uses the same rate of movement as it does in regular Traveller combat, so the referee need only pick a scale suitable to the units fighting and the battlefield he has planned.

For example, if two company-sized infantry forces are fighting, split into separate platoons and, possibly, squads, then the referee might use a scale of 50 metres to a square on graph paper. This will give enough room for each unit to occupy a square and a unit on foot will be able to move one square every ten rounds.

The benefit of using maps in this fashion is that everyone will know where every unit is, there will be no confusion during the battle and players will be able to make direct, tactical decisions.

The downside is that map-based battles take more time for the referee to prepare and can seem a little ‘flat.’ Traveller is, ultimately, a game of the imagination, and staring at graph paper with little symbols denoting units marked upon may not be the most exciting approach for some groups.

For when the referee wants to inject a little colour into his battles without spending a great deal of time preparing before the game begins, albeit at the cost of hyper-accuracy, we recommend using the freeform system described next.


Freeform Battles

Fundamentally, there is no reason why a mass combat cannot run in the same freeform way most firefights involving the players and a handful of enemies are played; the referee describes relative positions of the combatants, their actions, and how they respond to the actions of the players.

In this way, each unit is a single combatant and operates in much the same way as a single combatant in a firefight.

For example, the players might be leading their company against enemy-held fortifications, having first split it into three platoons (3 units) and then splitting a single specialised squad of explosives experts from one of those platoons (a fourth unit). The players themselves are each leading one of those platoons personally, or perhaps they have formed a temporary field base just out of range of the fortifications and are controlling their units via remote communications.

They have identified three weak points in the fortifications that will be the target of each platoon (perhaps a small bunker and two separate trench lines), while the demolitions squad has been ordered to approach one of the main walls of the fortified position while remaining unseen, using the platoons’ assault as cover.

This is where the combat begins. The referee will describe how long it takes for the platoons to reach their firing positions and begin attacking their targets, while the demolitions squad is making Stealth checks as it moves into position. The players make the appropriate roll and then perhaps start to react in alarm as the referee describes the gunships moving in to attack one of the platoons on their flank…

At the end of the day, it all comes down to the referee, his players, and their preferred style of play. If you and your players enjoy pouring over maps and figuring out the most efficient way to destroy the enemy, then map-based battles are likely what you are looking for.

If, instead, your players prefer to hear about the explosions ahead and bullets whizzing past their ears, while shouting orders at their men to advance, the freeform method may be more to your liking.

You will find Traveller can handle both styles, or even a mixture of the two, quite readily.

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