⚙️ House Rules

🎯 READ THIS FIRST: This campaign uses significant modifications to standard GURPS. These house rules are mandatory and change how the game works. Read carefully!
📄 PDF References: All house rules include links to source material. Click the PDF links to read the original rules. The PDFs are hosted on this site for your convenience.

Character Creation

Starting Points: Two Tiers

House Rule - No Official Source

Mundane Characters: 300 points

  • Elite operatives, executives, high-level officials
  • Many expert-level skills
  • Multiple advantages
  • No supernatural powers ever

Supernatural Characters: 150 points

  • Characters who will develop magic or psionics
  • Lower starting attributes (11-13 typical)
  • Fewer, more focused skills
  • Limited initial advantages
  • Powers develop during campaign

Effect: Choose your path at creation. Cannot switch later.

Disadvantages Give Zero Points

House Rule - No Official Source

Standard GURPS: Disadvantages give extra character points

This Campaign: Disadvantages give 0 points

Why:

  • Disadvantages are for character depth, not optimization
  • Prevents "disad farming" for points
  • Encourages meaningful character flaws
  • All characters built on exact point total (300 or 150)

Effect: Choose disadvantages for story value only. They don't increase your point budget.

All Attributes Cost 10 Points/Level

House Rule - Simplifies Basic Set p.14-17

Standard GURPS: Attributes have variable costs (ST 10/lvl, DX 20/lvl, IQ 20/lvl, HT 10/lvl)

This Campaign: All 10 attributes cost 10 points/level

Why This Works:

  • Simple: No need to remember different costs
  • Half-Stat Defaults: High attributes don't give free competence
  • Skills Matter: Must invest in skills regardless of attribute scores
  • Build Diversity: Spreading points is viable, min-maxing gives marginal gains

DX as Universal Combat Attribute:

Combat Type Required Attributes Cost for "15 Base"
Melee Specialist DX 16, HT 14 60 + 40 = 100 pts
Ranged Specialist PER 16, DX 14 60 + 40 = 100 pts
Combat Generalist DX 15, HT 13, PER 13 50 + 30 + 30 = 110 pts

Effect:

  • DX helps both melee and ranged (realistic - all combat needs coordination)
  • Specialists invest in DX + one other (HT or PER)
  • Generalists need DX + HT + PER (expensive but versatile)
  • Half-stat defaults prevent high attributes from being overpowered
  • Skills remain mandatory for actual competence

10-Attribute System

House Rule - Expands Basic Set p.14-17

Standard GURPS: 4 attributes (ST, DX, IQ, HT)

This Campaign: 10 attributes

Replaces With Cost
IQ KN, IN, PER 10/lvl each
Social Advantages CH, PR 10/lvl each
IQ/WILL split WILL (separate) 10/lvl
- QN (Quintessence) 10/lvl
ST, DX, HT Unchanged 10/lvl each

Effect: More granular character definition. All attributes cost 10 pts/level for simplicity.

Advancement: Experience & Growth

House Rule — No Official Source

Character advancement is earned through play, not awarded in bulk. There are three ways to earn Character Points (CP) each session:

1. Failed Roll Hashes (Skill & Attribute Growth)

Every time a PC fails a skill or attribute roll during play, they earn one hash mark toward that specific skill or attribute. When a skill or attribute accumulates 3 hash marks, the PC earns 1 CP that must be spent on that skill or attribute. Hash marks reset to zero after the CP is earned.

3 failed rolls on a skill/attribute = 1 CP toward that skill/attribute
Hashes Result
1–2 failed rolls Hash marks accumulate, no CP yet
3 failed rolls 1 CP earned — must be spent on that skill or attribute

Effect: Characters naturally improve in the areas they actually use and struggle with. A soldier who keeps failing Stealth will eventually get better at Stealth — not Diplomacy.


2. Session CP (Free Growth)

Every PC earns 1 CP at the end of each session, regardless of what happened. This CP is unrestricted — it may be saved across sessions or spent at the player's discretion on any skill, attribute, or advantage.


3. Disadvantage Roleplay Bonus (GM Award)

If a PC's disadvantage is brought into play during the session in a way that enhances the experience for the group — creating drama, complications, or memorable moments — the GM may award 1–2 bonus CP to that player. This CP is unrestricted.

  • 1 CP: The disadvantage came up meaningfully and affected the scene
  • 2 CP: The disadvantage drove a pivotal moment or significantly enriched the session

The GM is the sole judge of whether a disadvantage qualifies. Players should not engineer situations solely to trigger this reward.


Summary: CP Sources Per Session

Source CP Earned Restriction
3 failed rolls (per skill/attr) 1 CP per skill/attr Must go to that skill/attr
Session award 1 CP Unrestricted, may be saved
Disadvantage roleplay (GM) 1–2 CP Unrestricted

Skill Rules

Half-Stat Defaults

Standard GURPS: Skills default at (Attribute - Penalty)

This Campaign: Skills default at (Attribute ÷ 2) - (Penalty - 5)

Formula:

Default = (Controlling Attribute ÷ 2) - (Original Penalty - 5)

Examples:

Skill Normal Default Attribute Standard Half-Stat
Broadsword DX-5 14 14-5 = 9 (14÷2)-(5-5) = 7
Guns (Rifle) PER-4 13 13-4 = 9 (13÷2)-(4-5) = 7
Tactics IN-6 12 12-6 = 6 (12÷2)-(6-5) = 5
Fast-Talk CH-5 11 11-5 = 6 (11÷2)-(5-5) = 5

Effect:

  • High attributes don't give automatic competence
  • Must invest in skills to be good at them
  • Specialists become more specialized
  • Jack-of-all-trades becomes harder
  • Skills matter much more than standard GURPS

Melee Weapon Skills Default to (DX + HT) ÷ 2

House Rule - Modifies Basic Set p.174+

Standard GURPS: Melee weapon skills default to DX

This Campaign: Melee weapon and combat skills default to (DX + HT) ÷ 2

Includes:

  • All melee weapon skills (Sword, Axe/Mace, Knife, Spear, Staff, etc.)
  • Unarmed combat skills (Boxing, Brawling, Karate, Judo, Wrestling, Sumo Wrestling)
  • Fast-Draw (any)
  • Shield skills
  • Any DX-based combat skill involving close quarters

Why: Melee combat requires both coordination (DX) and stamina (HT). This makes HT relevant for melee fighters.

Calculating Melee Defaults:

  1. Calculate melee base: (DX + HT) ÷ 2
  2. Apply half-stat default formula: (Base ÷ 2) - (Penalty - 5)

Examples:

DX HT Melee Base Broadsword Default (Base - 5) Karate Default (Base - 4)
12 10 11 (11÷2)-(5-5) = 5 (11÷2)-(4-5) = 6
13 13 13 (13÷2)-(5-5) = 6 (13÷2)-(4-5) = 7
14 12 13 (13÷2)-(5-5) = 6 (13÷2)-(4-5) = 7
16 14 15 (15÷2)-(5-5) = 7 (15÷2)-(4-5) = 8

Effect: Melee fighters need both DX (finesse) and HT (endurance). Can't dump HT and rely only on DX.

Skills Remapped to 10 Attributes

House Rule - Based on Basic Set p.174+

Every skill has been remapped from the standard 4 attributes to the 10-attribute system:

Attribute/Base Skill Types
(DX+HT)÷2 Melee weapon skills, unarmed combat, Fast-Draw
(PER+DX)÷2 All ranged weapon skills (Guns, Bows, Thrown, Beam Weapons, etc.)
DX Stealth, acrobatics, technical physical (non-combat)
PER Observation, tracking, sensors, search
KN Academic knowledge, sciences, languages, magic spells
IN Engineering, tactics, problem-solving, analysis
HT Endurance skills, meditation, breath control
WILL Mental resistance, meditation, some esoteric skills
CH Diplomacy, fast-talk, acting, persuasion
PR Leadership, intimidation, interrogation

Effect: Attributes matter differently for different character types. See complete skill list for all mappings.

Combat Rules

Basic Speed from DX + PER

House Rule - Modifies Basic Set p.17

Standard GURPS: Basic Speed = (DX + HT) ÷ 4

This Campaign: Basic Speed = (DX + PER) ÷ 4

Why: PER is the ranged combat attribute. Including it in Basic Speed makes perception matter for initiative and dodge.

Examples:

  • DX 13, PER 14: Speed = (13+14)÷4 = 6.75
  • DX 11, PER 16: Speed = (11+16)÷4 = 6.75

Dodge: Still Basic Speed + 3

Basic Move from HT

House Rule - Modifies Basic Set p.17

Standard GURPS: Basic Move = Basic Speed (rounded)

This Campaign: Basic Move = HT ÷ 2 (round down)

Why: Makes HT relevant for mobility. Separates speed (reactions) from move (endurance).

Examples:

  • HT 10: Move = 10÷2 = 5
  • HT 11: Move = 11÷2 = 5.5 = 5 (round down)
  • HT 13: Move = 13÷2 = 6.5 = 6 (round down)
  • HT 14: Move = 14÷2 = 7

Melee Combat: Controlling Attribute = (DX + HT) ÷ 2

House Rule - No Official Source

Standard GURPS: Melee weapon skills use DX as controlling attribute

This Campaign: Melee weapon skills use (DX + HT) ÷ 2 as controlling attribute

How it works:

  1. Melee weapon skills use (DX + HT) ÷ 2 as their controlling attribute
  2. Buy skill points as normal (1 pt for Easy, 2 pts for Average, etc.)
  3. Roll vs your weapon skill to attack (just like standard GURPS)

Example Character:

  • DX 14, HT 12: Melee Base = (14+12)÷2 = 13
  • Broadsword (Average): Defaults at (13÷2)-(5-5) = 6
  • Spend 8 points: Skill goes to 13 (Default+7) — spend 20 points to reach skill 16 (Default+10)
  • Attack roll: 3d6 vs 13 (8 pts spent) or vs 16 (20 pts spent)

What Changed:

  • ✅ Roll vs weapon skill (unchanged)
  • ✅ Point costs normal (unchanged)
  • ⚠️ Controlling attribute is (DX+HT)÷2 instead of DX
  • ⚠️ Defaults calculated from (DX+HT)÷2

Effect: Both coordination (DX) and endurance (HT) matter for melee combat skills. Still roll normally to hit.

Ranged Combat: Controlling Attribute = (PER + DX) ÷ 2

House Rule - No Official Source

Standard GURPS: Ranged weapon skills use DX as controlling attribute

This Campaign: Ranged weapon skills use (PER + DX) ÷ 2 as controlling attribute

Why: Ranged combat requires both perception (PER) to acquire and track targets, and coordination (DX) for steady aim and trigger control. Mirrors the melee formula structure.

How it works:

  1. Ranged weapon skills use (PER + DX) ÷ 2 as their controlling attribute
  2. Buy skill points as normal (1 pt for Easy, 2 pts for Average, etc.)
  3. Apply range/size/speed modifiers
  4. Roll vs your modified weapon skill to attack (just like standard GURPS)

Example Character:

  • PER 14, DX 12: Ranged Base = (14+12)÷2 = 13
  • Guns (Rifle) (Easy): Defaults at (13÷2)-(4-5) = 7
  • Spend 8 points: Skill goes 13, 14, 15, 16, 17 (at Base+4 equivalent)
  • Target at -4 range penalty
  • Attack roll: 3d6 vs 13 (17 skill - 4 range)

What Changed:

  • ✅ Roll vs weapon skill (unchanged)
  • ✅ Apply range/targeting modifiers (unchanged)
  • ✅ Point costs normal (unchanged)
  • ⚠️ Controlling attribute is (PER+DX)÷2 instead of DX
  • ⚠️ Defaults calculated from (PER+DX)÷2

Symmetry with Melee:

Combat Type Formula What You Need
Melee (DX + HT) ÷ 2 Coordination + Endurance
Ranged (PER + DX) ÷ 2 Perception + Coordination

Effect: Both perception (spotting targets) and coordination (steady hands) matter for ranged combat. DX is now universally useful for all combat types. Still roll normally to hit.

Damage: Know Your Own Strength (KYOS)

Pyramid #3/83 p.16 — Sean Punch (September 2015)

Standard GURPS: Swing = Thrust + various (1d-2 to 2d+2 depending on ST); damage progression is linear and unrealistic at higher ST values.

This Campaign: Uses the KYOS Revised Strength Table. Damage is logarithmic — each +1 to ST represents roughly a 10% increase in actual strength. Swing is no longer simply Thrust + 2; instead both values are read directly from the table.

Revised Strength Table (Human Range ST 8–16):

ST Basic Lift Thrust Swing Description
813 lbs1d-41d-2Two-thirds as strong
916 lbs1d-31d-1Three-quarters as strong
1020 lbs1d-21dAverage person
1125 lbs1d-11d+1Half again as strong
1232 lbs1d2d-1Twice as strong
1340 lbs1d+12d-1Twice as strong
1450 lbs1d+12dThree times as strong
15*63 lbs2d-12d+1Three times as strong
16**80 lbs2d2d+2Four times as strong

* ST 15 requires Unusual Background (5 pts). ** ST 16 requires Unusual Background (10 pts). These are the human hard limits.

Effect: More realistic damage scaling. A ST 12 character does noticeably more swing damage (2d-1) than under the old Thrust+2 system (1d+1). High ST is more meaningful and the logarithmic scale prevents inflation at the top end.

Grapple Power (GP) — Lifting ST in Grappling

Campaign House Rule — uses KYOS Lifting ST (Pyramid #3/83 p.18)

In this campaign, ST is divided into Striking ST (SST), Lifting ST (LST), and Hit Points (HP). Grappling is the one place where Lifting ST directly affects combat outcomes — raw muscle mass and leverage determine who controls a grapple.

Base grapple CP comes from Striking ST (normal thrust via GCS/GGA), unchanged. After base CP is calculated, add a Grapple Power bonus based on the Lifting ST difference between attacker and defender:

GP = max(0, floor((Attacker LST − Defender LST) ÷ 3))

This bonus applies to:

  • CP inflicted on a successful grapple or control attack
  • CP removed on a successful Break Free or Reduce Control action

GP never goes below 0 — being weaker gives no penalty to base CP, only no bonus.

Examples:

Situation Attacker LST Defender LST GP Bonus
Evenly matched humans1212+0
Strong vs. average1612+1
Power armor vs. human2012+2
Superhuman vs. power armor2820+2

Effect: Bigger, stronger characters are meaningfully harder to grapple and easier to control. A highly-trained fighter with modest LST can still grapple effectively — their base CP from Striking ST and technique remains intact. But against a power-armored opponent or a genuine giant, raw leverage starts to tell.

📖 See The 10 Attributes → ST Components for SST, LST, and HP costs.

Multiplicative Modifiers (Dice + Adds)

Standard GURPS: Option to use Dice+Adds for damage

This Campaign: Using Dice+Adds system

How it works:

  • Damage listed as dice + adds (e.g., 2d+3)
  • Multipliers apply to BOTH dice and adds
  • Makes damage scaling more consistent

Example:

  • Broadsword does 2d+3 cutting
  • ×1.5 for cutting becomes (2d+3)×1.5 = 3d+4

Effect: Cleaner damage calculations with multipliers.

Magic & Supernatural Rules

Magic Uses KN (Not IQ)

House Rule - Modifies GURPS Magic p.8

Standard GURPS: Spells are IQ-based skills

This Campaign: Spells are KN-based skills

Why:

  • KN = Knowledge, including magical lore
  • Separates magical learning from other mental abilities
  • Prevents "super-wizard" who's also tactical genius and perception expert

Effect: Mages invest in KN for spell skills, just as fighters invest in DX/PER for combat.

QN (Quintessence) Powers Magic

House Rule - New Attribute

Standard GURPS: Spells cost FP

This Campaign: Spells cost QP (Quintessence Points)

QN Attribute:

  • QN = Quintessence (10 pts/level)
  • QP = QN score (QN 12 = 12 QP base)
  • Magery doesn't increase QP, but higher Magery may reduce spell costs or improve effectiveness
  • Recover QP like FP (10 min rest = 1 QP)

Magic System:

  • Spell Skill: Based on KN
  • Spell Cost: Paid in QP (not FP)
  • Spell Resistance: WILL (mental strength)
  • Magic Sense: QN + Magery level

Example Mage:

  • KN 14: Spell skills at 14 base
  • QN 12: 12 QP total
  • Magery 2: Improves spell effectiveness and reduces costs
  • WILL 12: Resist spells at 12
  • Magic Sense: 14 (QN 12 + Magery 2)

WILL for Resistance Only

House Rule - Clarifies Basic Set p.16

Clarification: WILL does NOT power magic or psionics

WILL is used for:

  • Resisting mental influence
  • Resisting fear and terror
  • Extra effort and pushing limits
  • Resisting spells that target the mind
  • Psionic contests (defense)

WILL is NOT used for:

  • ❌ Casting spells (that's KN + QN)
  • ❌ Powering psi abilities (that's IN or PER)
  • ❌ Magic skill rolls

Effect: WILL is purely defensive/resistance. Prevents "WILL super-build."

Optional Rules in Effect

The following optional rules from various GURPS books are active in this campaign:

  • Half-Stat Defaults - Pyramid 3/65 p.30
  • Multiplicative Modifiers (Dice+Adds) - Basic Set p.269
  • Know Your Own Strength (KYOS) - Pyramid #3/83 p.16
  • Afflictions - Powers (for special attacks)
  • Modular Abilities - Powers (limited use)

Standard GURPS Rules NOT Used

The following standard or common optional rules are NOT active:

  • Lifting ST adds to damage - ST bought for damage only
  • Disadvantage points - All disads give 0 points
  • Standard 4-attribute system - Using 10 attributes
  • IQ attribute - Replaced by KN, IN, PER
  • Charisma advantage - Replaced by CH attribute
  • Standard defaults - Using half-stat defaults
  • Swing = Thrust + 2 (Kevin Smyth) - Replaced by KYOS damage table
  • Standard ST damage table (Basic Set p.16) - Replaced by KYOS Revised Strength Table
  • True AI - Banned by G.U.A.R.D. Treaty after AI Wars (world lore, not mechanic)

Quick Reference: Key Formulas

Element Formula Notes
Basic Speed (DX + PER) ÷ 4 Initiative and dodge base
Basic Move HT ÷ 2 Round down
Dodge Basic Speed + 3 Active defense
Melee Base (DX + HT) ÷ 2 Controlling attribute for melee weapon skills
Ranged Base (PER + DX) ÷ 2 Controlling attribute for ranged weapon skills
Skill Default (Attribute ÷ 2) - (Penalty - 5) Half-stat defaults
Swing Damage See KYOS Revised Strength Table Pyramid #3/83 p.17
QP (magic energy) = QN Magery 0 = +0, Magery 1 = +5, etc.
Magic Sense QN + Magery level Roll to detect magical effects