OVERVIEW

INTRODUCTION

The Xero Sum Engine (XSE) is a tabletop roleplaying game framework designed for 2–6 players, with robust core mechanics that can be applied to most genres or settings, whilst remaining lightweight enough to keep the story at the center of the action.

One player takes on the role of the Game Master (or GM) and acts as both referee and storyteller, and everyone else is a player character (or PC) within the unfolding story.

The rules, skills, and equipment included in this SRD do not cover more fantastical elements, such as magic or psionics. This SRD will be updated as new rules are play-tested and refined.

This document outlines the Community Resource & Morale Rules added with the XSE SRD v1.1. 

A worksheet to make tracking community resources and morale easier is available for download at XeroSumGames.com/Workbooks.

 

KEY FEATURES OF THE XERO SUM ENGINE:

REALISM

XSE is a good fit for games with grounded storylines, particularly those in the survival, noir, espionage, western, war, low fantasy, or hard sci-fi genres. The focus is on ordinary people in extraordinary situations and while the actions of the characters might be heroic, they are not super-heroes, gods, wizards, or chosen ones.

Combat in the Xero Sum Engine is brutal, unforgiving, and can have lasting consequences for characters. Players should never enter combat lightly and should actively seek alternatives. Combat is not the only threat to characters, and starvation, sickness, or dying of exposure are a possibility, and falling from a window can be lethal. 

To ensure their long-term survival, players will need to focus on problem solving, diplomacy, and the use of social skills. 

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FAST PACED

The Xero Sum Engine utilizes a simple d6 game mechanic that can intuitively facilitate any challenge or task resolution with ease.

XSE prioritizes realism and momentum over needlessly complex rules to keep the narrative at the center of the game.

 

STORY DRIVEN

Collaborative storytelling fuels the Xero Sum Engine, and it provides players with various tools to drive the narrative. These tools include Insight Dice, Filling in the Gaps, Making The Case, First Impressions, and Gut instinct rules, as well as rules for Recruitment and Community building. 

 

DICE & NAMING CONVENTIONS

2d6: Most checks in the XSE SRD use 2 six-sided dice, adding the scores together to get a final tally. 

xd6: When multiple dice are required for a dice check, it is written in the format xd6, such as 3d6 or 4d6. The final score is determined by adding together all the dice. 

d3: Rolling a six-sided dice and halving the result (rounding down), for a result of 1-3.

Game Master: The player who takes on the role of facilitator, storyteller, and referee, the Game Master defines the environment, populates the world and propels the story forward.

PC: A player character (also referred to just as a character) is the personification of the player in the story.

NPC: Non-player characters (NPCs) are other characters that the players interact with and are brought to life by the Game Master.
 

Dice Check: Also called Dice Rolls, a Dice Check is the basic mechanic for seeing if something a character does is successful and involves rolling two 6-sided dice and totally up the sum of both dice.
 

Modifiers: Each Dice Check can be positively or negatively affected by modifiers that are tied to attributes, skills, and conditions.