House Rules

S4 uses the following optional rules in addition to the Cypher System. Other GMs are welcome to disregard part or all of this section if desired.

Exploding Die

When a player rolls a natural 20 she takes the major effect or 4 additional damage as usual but the die is poised to explode. This means that the player rolls again and on any result besides another natural 20 play moves forward as usual. If another 20 is rolled a second major effect or an additional 4 points of damage is added. This continues until the player no longer rolls 20.


Recovery rolls may be made in any order. Rather than following the track from 1 round to 10 hours, you may, more realistically, choose what type of recovery (rest) you would like to take. As soon as the 10 hour rest is used the recovery track is reset.

Alternate Effects, Lasting & Permanent Damage

The GM is encouraged to use the optional trading damage for effect and the lasting and permanent damage rules as well as the alternatives of weakness and inability found on pages 224 to 226 of the Cypher System Rulebook.

The Metric System

The future civilization of S4 uses the metric system. All measurements will be given in metrics in these webpages and also at the game table. In most cases, the imperial figure follows the metric in parenthesis, but this is not the case for the standard Cypher lengths of immediate, short, and long. They are as follows:

Immediate Short Long
No more than 3 m (~10 feet) 15 m (~50 feet) or so 30 m (~100 feet) or so