Mneme CE Combat Rules

Mneme Variant Combat Rules for the Cepheus Engine tabletop RPG system. These are streamlined, narrative-focused combat rules designed to reduce mental overhead and speed up gameplay while maintaining tactical depth.

Overview

The Mneme Combat System takes what would have been many rolls and boils it down to One Roll per Turn in which the value is symmetrically beneficial or detrimental to both the PC and their opposition. The Referee doesn't roll for NPCs—instead, the PC rolls against a Difficulty set by the Referee, with the Effect of the roll determining outcomes for both sides.

Design Philosophy: Named after Mnemosyne, the muse of memory, the goal of the system is to be easier on the mind to run.

Credits

Writing: Justin Aquino
Art: Nicco Salonga
Editing: Adrian Martinez
Play Testing: Mike Dulay

Legal Notice

These are Variant Rules, specifically called the Mneme variant rules. Please credit the Mneme Variant Rules when deriving content from this work.

This Product is derived from the Traveller System Reference Document, and other Open Gaming Content made available by the Open Gaming License (OGL).

Cepheus Engine and Samardan Press are the trademarks of Jason "Flynn" Kemp.

Core Combat Rulebook

#	Chapter	Description
1	Chapter 1: Introduction	What are the Mneme Variant Rules? Key benefits, design philosophy
2	Chapter 2: Core Mechanics	One Roll per Turn, Task Resolution, Referee doesn't roll
3	Chapter 3: Dice Mechanics	Modifiers, Difficulty, Effects, Advantage/Disadvantage
4	Chapter 4: Running Combat	Narrative combat, 3 Key Factors, Combat Cycle
5	Chapter 5: Conditions	Awareness, Terrain, Time, Weather, Visibility
6	Chapter 6: Actions	Action types, Movement, Reactions
7	Chapter 7: Outcomes	Damage, Success/Failure effects
8	Chapter 8: Character Conditions	Health states, mental conditions
9	Chapter 9: Equipment	Weapons, armor, equipment traits
10	Chapter 10: Quick Characters	Sample NPCs, templates

Quick Reference Tables

Difficulty Number Table

Description	Difficulty	Dice Modifier
Easy	4	+4
Routine	6	+2
Average	8	+0
Difficult	10	-2
Very Difficult	12	-4
Formidable	14	-6

Superiority Table

Situation	Modifier
Superior Firepower	+1 to +3
Superior Position/Action	+1 to +2

Key Principles

One Roll Per Turn

To speed up play and keep the focus on the back-and-forth conversation between the Referee and Players, the Mneme system uses one roll per turn that determines both the PC's success AND the adversary's response.

Referee Doesn't Roll

The Referee sets the Difficulty based on circumstances, but does not roll dice for NPCs. The PC rolls against this Difficulty, and the Effect (how much they succeed or fail by) determines what happens to both sides.

Effects Matter

The Effect (the difference between the roll and the Difficulty) determines:

How successful the action is
How much damage is dealt or received
What conditions change
Whether there are costly consequences

Symmetrical Outcomes

The system is designed to be symmetrical—a high Effect benefits the PC and harms the adversary proportionally. A low or negative Effect means the PC suffers while the adversary gains advantage.