[Let’s Study Coriolis Part 3] Systems & Combat

Posted: February 3, 2017 by pointyman2000 in Coriolis, Let's Study, Modiphius, Roleplaying Games
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Welcome back everyone. Today we’re taking a peek at the systems behind Coriolis. If you’re familiar with Mutant: Year Zero, you’ll find this bit familiar, but we’ll still go through everything for the sake of those entirely new to it.

Rolling Dice

When it comes to the basic resolution mechanic of the game, a player puts together a pool of six-sided dice equal to the appropriate skill and corresponding attribute. This is then modified by gear or external factors like bonuses and penalties. In order to succeed, you need to be able to roll at least 1 six. Rolling more sixes means that you get to unlock bonus effects.

Honestly this is possibly one of the simplest base resolution systems I know of. It’s a joy to teach, since you just tell players to watch for sixes.

Critical Successes

Rolling three or more sixes elevates the success of the attempt to a Critical Success that unlocks  bonuses depending on the skills being used.


If you don’t roll any sixes then something goes wrong and the GM gets to decide what happens to you. The fun rule here is that the GM is forbidden to just say that nothing happens. Failures must always have consequences, and that amps up the drama of the situation a bit.

Divine Assistance

Player characters may also pray to the Icons for help. This means that you get to reroll all dice that do not show sixes. Which Icon you pray to depends on the skill being rerolled. Praying doesn’t count as an action and takes no time.

The Dark Between the Stars

This isn’t without a cost of course. When the Players use the power of the Icons to help, the GM gets a little boost as well in the form of getting Darkness Points. These can then be used by the GM to enhance his own forces in game.


Right, so now that we know the basic rules for the game, what happens when words fail and the weapons start coming out?


To find out who goes first, each of the participants in a combat roll one die. The result of each die is the initiative score for that person, with the ones who rolled highest going first. Ties are re-rolled until all are resolved.

Initiative is only done at the start of a fight and remain so unless there are other actions taken to raise your initiative score such as:

  • Surprise attacks grant +2 to your initiative score but only for the first turn
  • The Combat Veteran talent lets a player make their initiative roll with two dice instead of one, choosing the better result.
  • Certain actions can be used to maneuver to a better position
  • Skill tests that score critical successes sometimes allow for raising intiative
  • Weapons give a temporary initiative bonus.


All players get 3 Action Points (AP) to spend each turn. Slow actions cost all 3 AP to perform, while speedier actions take less, with free actions costing no AP.

Examples of the actions are as follows:

Slow (3 AP)

  • Firing an aimed shot
  • Firing full auto
  • Administering First Aid

Normal Actions (2 AP)

  • Attacking in close combat
  • Firing a normal shot
  • Reloading a weapon

Fast Actions (1 AP)

  • Taking cover,
  • Picking up an item
  • Parrying in close combat

Free Actions

  • Using your armor against an attack
  • Defending in an opposed roll
  • Shouting something to a comrade


Range is divided into four categories: Close (2m), Short (20 m), Long (100m) and Extreme (1 km).


A Fast Action can let a player move about 10 meters. There are talents that allow for a faster Movement Rate, but generally only non-humans and vehicles can move faster than that.

Melee Combat

Making an attack is fairly simple in Coriolis. Melee is resolved by making skill check using the Melee Combat skill. The Enemy then chooses if they’ll take the blow or attempt to defend (which they can only do if they have AP left to do so!) Interestingly, if the defender is an NPC, then the GM also has to spend an additional 1 DP to defend!

If the Melee Combat roll is successful, then the attack hits and deals damage equal to the Weapon’s Damage rating. Each additional six on the roll can also be spent among the following: Increase Damage, Deal Critical Injury, Strike Fear, Raise Initiative, Disarm or Grapple.


Defending is a contested Melee Combat check, which is rolled at the same time against the attacker. For every six you roll as a defender you can choose among the following: Decrease Damage, Counterattack, Critical Injury, Disarm, Raise Initiative

This means that there’s an interesting option of taking a hit in full  just so you can deal a solid counter to your opponent, and dropping them on their turn.

Ranged Combat

Unlike Melee Combat, Ranged Combat has a few more items to consider. Target size has a penalty or bonus to the attack roll, and Range modifiers also apply to the difficulty.

A successful Ranged Combat roll allows you to deal Weapon Damage to the target, and extra sixes may be spent on the following: Increase Damage, Critical Injury, Suppressive Fire, Raise Initiative and Disarm.

Quick Attacks

There are Quick Variants of each of the combat types done at the expense of accuracy, suffering a -2 penalty to the attack roll. Melee Quick Attacks cost only 1 AP but can only be performed with light weapons. For Ranged Combat Quick Attacks, the cost is also reduced to 1 AP, but can only be used against enemies at Close or Short Range. If a character makes three quick shots in the same turn, the clip runs out and the weapons needs to be reloaded.

Stress Damage

If a character is reduced to zero Mind Points (MP), they suffer a breakdown, collapsing from fear or anxiety. This is especially interesting given how Suppressive Fire can be used to deal Stress Damage to a pinned target. Broken down targets can follow simple commands but cannot take any action that requires dice rolls.

Command or Medicurgy can be used to treat someone who has suffered a breakdown. If the roll is successful, the person being calmed down regains MP equal to the number of sixes on your roll. Each attempt is a slow action and each person can only try once.


Regular damage is tracked by Hit Points. Armor is used to mitigate this damage, and as a free action the attacked Player rolls a number of dice equal to their Armor Rating, each six lowers the damage by 1. If the damage from the attack is reduced to zero, they avoid critical injuries as well.

Critical Injuries

When using the Critical Injury option in an attack roll, a player has to spend a number of extra sixes equal to the Crit value of the weapon being used to deal it. If successful the attacker rolls a d66 on a table to determine the flavor of lasting pain inflicted upon his target.

Critical injuries have a short term and long term effect. Short term effects are often Stunned, or sometimes the target is forced to drop a held item. Long Term effects are penalties that they carry with them until the injury is treated properly.


Coriolis is a game that loves it’s vehicles. Combat therefore has a section for fighting on (and against) vehicles, and most of the rules are similar to the ones above, with the use of the Pilot skill as a means of control for maneuvers. You can also ram enemies with the vehicle, giving me happy mental images of a daredevil smashing into an opponent at full speed with a grav bike.


Coriolis uses a simple system with carefully considered subsystems to deliver a surprisingly tactical experience. There’s plenty of stuff to enjoy here whether you’re the type to prefer the “Theater of the mind” type of play, or if you’re a square-counting battlemat sort of person.

Next time, we’ll take a peek at the Spaceships and Star Travel rules for Coriolis!



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