Salt & Steel: Attributes and Stats

Document Type: Design — Character Systems
Status: Draft v1.0
Last Updated: 2026-04-24
See Also: Classes and Ascendancies | Skill Atlas | Leveling and Progression | GURPS Adaptation Research

Overview

Salt & Steel's attribute and stat system is a direct implementation of GURPS 4th Edition's character model, adapted for real-time ARPG play. The design goal is to preserve the mechanical coherence and feel of GURPS — specifically the bell curve probability model and the interconnected secondary stat derivations — while presenting it in a form accessible to players who have never touched a tabletop RPG.

The system achieves this through a clear visual language: the GURPS numbers live under the hood, driving the probability calculations; the player sees clean, comprehensible derived stats (Dodge 9, HP 120, etc.) that map predictably to real experience. Designers and engineers need to understand both layers. This document covers both.

Primary Attributes

The four GURPS primary attributes are the foundation of all character stat calculations. Everything else derives from these four numbers. Critically, the ratios between them are as important as the absolute values — a character with ST 14 and DX 10 feels dramatically different from a character with ST 10 and DX 14, even if they have spent the same character points.

Strength (ST)

"The sea respects force. So does the crew."

Point Cost: 10 character points per level above base 10

What ST Governs Directly:

Melee Damage: The GURPS Thrust and Swing damage dice are the foundation of all melee damage output. The formula is nonlinear, which is critical to the feel of ST investment:

ST	Thrust	Swing	Effective Melee Damage Feel
8	1d-3	1d-2	Barely scratches; needs critical hits to matter
9	1d-2	1d-1	Below average; workable with good skill
10	1d-2	1d	The baseline human; average damage
11	1d-1	1d+1	Noticeably stronger; cuts through common armor
12	1d-1	1d+2	Clearly powerful; most enemies feel this
13	1d	2d-1	Military-grade strength; real boarding fighter
14	1d	2d	The pirate archetype peak; hits like a cannon shot
15	1d+1	2d+1	Exceptional; intimidates by reputation alone
16	1d+2	2d+2	Monstrous human; deck-clearing presence

Note: ST damage uses GURPS notation where 2d = 2 six-sided dice, and modifiers adjust the total. Salt & Steel scales all damage by ×10 for ARPG numbers: GURPS 2d (avg 7) becomes S&S 70 average damage before wound modifiers, armor, and location.

Basic Lift (BL): ST² ÷ 5 lbs. Governs encumbrance and carry capacity. A ST 14 character has BL 39.2 lbs — a meaningful limit when loading out with heavy armor and weapons for boarding.
Crew Intimidation: +1 to Intimidation skill rolls per 2 points of ST above 10 (so ST 14 provides +2 to Intimidation). Enemies with ST significantly lower than the player character have their Will rolls modified negatively by the size differential.
Grapple Strength: ST directly determines the outcome of grapple contests (ST vs. ST).
Boarding Force: In boarding calculations, crew effectiveness is partially derived from average ST of the boarding party.

Design Note — The ST/HP Relationship: In GURPS, HP defaults to ST. In Salt & Steel, we preserve this default but make it more visible: investing in ST automatically increases your HP pool at the 1:1 rate (×10 scale), creating a "combat stats" axis where ST investment improves both offense and survivability simultaneously. This is intentional and creates the Buccaneer archetype's coherence.

Dexterity (DX)

"The difference between the quick and the dead is about three centimeters and a tenth of a second."

Point Cost: 20 character points per level above base 10 — the most expensive primary attribute

Why DX Costs More: DX provides the default roll for more skills than any other attribute — every physical combat skill, every movement skill, every precision task. It also directly feeds Basic Speed, which feeds Dodge. In GURPS terms, DX is worth twice as much as ST or HT because it does twice the mechanical work.

What DX Governs Directly:

Combat Skill Defaults: All physical combat skills use DX as their base. When a player invests in DX, every point spent also improves the baseline probability of every physical combat action — an instant-effect benefit across all equipped weapon skills.
Basic Speed (DX+HT)÷4: Speed governs attack cadence and the critical Dodge value.
Active Defense (Dodge) Base: Dodge = Basic Speed + 3, rounded down. At DX 14 + HT 10, Basic Speed = 6, Dodge = 9. This is the core defensive value of DX-primary characters.
Ranged Attack Foundation: All Guns, Bow, and Thrown Weapon skills default to DX. A character with DX 14 fires pistols at DX 14 before any additional skill investment — already at 90.7% base hit rate.
Ship Handling Precision: DX-based Seamanship and Sailing checks are used for precision maneuvers (threading between rocks, cutting the enemy's bow, controlled boarding approach).

The DX Dilemma: Because DX costs 20 pts/level vs. ST's 10 pts/level, the decision to invest in DX is the game's most significant early optimization question. Two levels of DX (40 pts) buy four levels of ST (40 pts). The DX investment is worth it for characters whose primary value comes from skill accuracy and defense; the ST investment is worth it for characters whose primary value comes from damage output and HP. This tradeoff is the mechanical heart of the Buccaneer vs. Corsair vs. Privateer comparison.

Intelligence (IQ)

"The chart is wrong. It's always been wrong. The sea moved. I know where it actually is."

Point Cost: 20 character points per level above base 10 — tied with DX as the most expensive

Why IQ Costs More: Like DX, IQ provides defaults for a broad category of skills — all mental skills, social skills, knowledge skills, and (critically for Salt & Steel) all magical skills. Will and Perception both default to IQ, meaning IQ investment also improves curse resistance and awareness simultaneously.

What IQ Governs Directly:

Mental and Social Skill Defaults: Navigation, Tactics, Fast-Talk, Merchant, Occultism, and all spell-college skills default to IQ. An IQ 14 character is immediately better at all of these before spending a single additional skill point.
Will (= IQ by default): Resistance to mental effects, curse attacks, Fright Checks, and social manipulation. High Will is the primary defense against the game's supernatural content.
Perception (Per) (= IQ by default): Trap detection range, treasure sensing distance, enemy awareness (stealth contests), and weather-reading accuracy. High Per creates a character who knows things before they become crises.
Spellcasting Foundation: All spell colleges use IQ as their base skill. The Navigator's IQ 14 means every spell in the game starts at a 90.7% baseline before any additional investment.
Tactical Analysis: Strategy and Tactics skills (IQ-based) determine when the player receives terrain and enemy pattern information. High IQ makes the game's information layer richer — more visible enemy behaviors, longer-range treasure detection, better environmental reading.

The IQ Social Machinery: In the GURPS Social Engineering translation (see [Faction Systems]), all social skill contests use IQ-based skill rolls modified by faction Reaction Scores. Every point of IQ is a point of advantage in every negotiation, every intimidation, every performance. The Navigator and Mystic classes who invest heavily in IQ do not just cast better spells — they have fundamentally richer social interactions with every NPC in the game.

Health (HT)

"The sea has tried to kill me fourteen times. Fourteen times it has been wrong."

Point Cost: 10 character points per level above base 10

What HT Governs Directly:

Fatigue Points (FP) (= HT by default): FP is the universal action resource (see Fatigue System section). HT investment is the most direct way to expand your action economy. Each level of HT = 1 more FP = more dodges, more spells, more sprinting, more powerful attacks before exhaustion sets in.
Knockdown Resistance: When damage exceeds HP/2 in a single hit, the target must roll 3d6 ≤ HT to avoid being knocked down (stunned, prone). A HT 14 character passes this roll 90.7% of the time; a HT 9 character passes it only 37.5% of the time. High HT means you stay on your feet when others are going down.
Death and Unconsciousness Resistance: When HP drops to 0 or below, HT rolls are required to stay conscious. When HP drops to −HP (negative your max HP), HT rolls are required to not die. The Mariner with HT 14 can absorb punishment that would kill any other class.
Disease and Poison Resistance: All environmental hazard effects (tropical fever, scurvy, curse infection, alchemical exposure) use HT as the base resistance roll.
FP Recovery Rate: HT affects baseline FP recovery: 1 FP per 10 minutes of rest (GURPS baseline), translated to 1 FP per 5 seconds out of combat in real-time. Higher HT slightly accelerates this baseline.
Basic Speed Contribution: Basic Speed = (DX + HT) ÷ 4. Unlike ST, HT contributes to Speed — meaning HT investment slightly improves both FP and Dodge simultaneously. This makes HT the "efficient" defensive attribute: it improves survivability, action economy, and passively nudges defensive stats.

The HT/ST Cost Symmetry: ST and HT both cost 10 pts/level. ST provides offense (damage dice) and HP; HT provides resilience (FP, knockdown resistance, HT rolls) and contributes to Speed. They are designed to be the "affordable" attributes that pure combat and endurance builds invest in after the expensive DX/IQ decisions are made.

Secondary Characteristics

All secondary stats derive from primary attributes according to GURPS formulas. Each secondary stat can be bought up independently at reduced cost — allowing targeted stat optimization without expensive primary attribute investment.

The visual convention: secondary stats are always displayed in their Salt & Steel scaled form (×10 for HP/FP, direct values for percentages and roll targets). The underlying GURPS number is used by the engine; the player sees the derived game number.

Hit Points (HP)

Default Formula: HP = ST (GURPS) → ×10 for in-game display
Buy-Up Cost: 2 character points per HP (GURPS rate, unscaled; provides +10 HP in-game)
GURPS Atlas Cost: 1 Skill Point per +10 HP

HP is the character's survivability pool. At 0 HP, the character is at risk of unconsciousness (HT roll required each turn). At −HP (negative of their max HP), another HT roll for death. At −5×HP, death is immediate.

The HP/ST Relationship
Because HP defaults to ST, Buccaneer characters (ST 14) begin with 14 HP (140 in-game) — the highest starting HP of any class. A Navigator (ST 8) begins with 8 HP (80 in-game). This disparity is why the Navigator must maintain distance and manage threat — a single good hit is far more dangerous to them.

HP Scaling Note
Salt & Steel multiplies all GURPS HP values by 10 for ARPG feel. A GURPS character with 14 HP becomes a Salt & Steel character with 140 HP. All damage values are correspondingly scaled. The underlying probability mathematics are unchanged — a hit that deals 7 GURPS damage (70 Salt & Steel damage) to a target with 14 GURPS HP (140 in-game) still represents approximately 50% of their health pool, triggering the same knockdown threshold as the original rules intended.

HP Threshold Effects:

At ≤ 50% HP: Wound effects become visible in the character animation (favoring an injury, different movement)
At ≤ 33% HP: Minor injury penalties begin (−1 to all non-HT rolls from accumulated wounds) — unless High Pain Threshold Keystone is allocated
At ≤ 20% HP: Some classes gain desperate bonuses (Swashbuckler Ascendancy, Oracle's Borrowed Time, etc.)
At 0 HP: Incapacitation risk (HT roll each 3 seconds)
At −HP: Death risk (HT roll each 3 seconds; failure = death)
At −3×HP: Instant death, no roll

Fatigue Points (FP) — The Universal Action Resource

Default Formula: FP = HT (GURPS)
Buy-Up Cost: 3 character points per FP (GURPS rate)
GURPS Atlas Cost: 2 Skill Points per +1 FP (more expensive than HP per point because of the action economy value)

FP is the most important resource in Salt & Steel's real-time adaptation. It replaces both traditional mana and traditional stamina with a single unified pool that governs all action economy decisions.

FP Costs (per action):

Action	FP Cost	Notes
Active Dodge	1 FP	Universal; every dodge costs energy
Second Dodge within 2 seconds	1 FP	Stacks with first-dodge cost
Third+ Dodge within 2 seconds	2 FP	Cascading penalty for desperate evasion
Parry (melee)	0 FP	Standard parry is free; the commitment, not the energy
Block (shield)	0 FP	Standard block is free
All-Out Attack (any variant)	1 FP	Committing fully to offense costs energy
Sprint (per 10 seconds)	1 FP	Sustained movement exhaustion
Swim (per 10 seconds)	1 FP	Continuous swimming is tiring
Climb (per 10 seconds)	1 FP	Rigging and cliff climbing
Basic Spell (1 FP cost)	1 FP	Standard GURPS spell FP cost
Major Spell (5 FP cost)	5 FP	Area and high-effect spells
Signature Ability (Ascendancy)	2–5 FP	Varies per ability
Boarding Rush (Reaver)	2 FP	Stated in class document

FP Threshold Effects:

At ≤ 1/3 FP (at or below FP/3, rounded down): Move and Dodge halved. The visual display shifts — the character's movement becomes slightly labored, their dodge animations shorter. Audio: heavier breathing. This is the "danger zone" — a character here is significantly more vulnerable.

At 0 FP: Each additional point of FP spent costs 1 HP instead. The character is running on life force. The urgency of this situation is communicated clearly: red border on the FP gauge, heartbeat audio effect, screen vignette tightening. Most characters cannot survive long at 0 FP in active combat.

At below 0 FP: Each turn in combat where FP is still being drained costs 1 HP. Characters at negative FP who are still fighting are in genuine peril.

FP Recovery:

Condition	FP Recovery Rate
Complete rest (no movement, no combat)	1 FP per 5 seconds
Light movement (walking, no combat)	1 FP per 10 seconds
Active combat (moving, fighting)	0 FP regeneration
Specific recovery items (rum, rations)	Flat FP restoration
Fit Advantage (Atlas Survival Shoal)	+20% to all recovery rates
Very Fit (2 Fit Advantage nodes)	+40% to all recovery rates
Quartermaster Ascendancy aura	+1 FP per 15 seconds in combat

FP and the Build Meta
FP is the parameter that determines how long a character can sustain their playstyle before exhaustion changes the situation. A spell-heavy Navigator with FP 10 must be careful not to blow through their pool in the opening of a fight; a Sea Dog Mariner with FP 18 can dodge, sprint, and grapple for much longer before the exhaustion penalty kicks in. FP build decisions (buying up FP on the Atlas, investing in HT, taking the Fit advantage nodes) are distinct from damage-focused decisions but no less important for survivability.

Will

Default Formula: Will = IQ
Buy-Up Cost: 5 character points per level (GURPS rate)
GURPS Atlas Cost: 4 Skill Points per +1 Will

Will governs resistance to all mental and supernatural effects. In Salt & Steel's world, where cursed artifacts, sea spirits, and enemy sorcerers are genuine threats, Will is a frontline defensive stat for any character engaging with the game's supernatural content.

Will Applications:

Situation	Roll
Resisting enemy curse spells	3d6 ≤ Will
Resisting supernatural Fright Checks	3d6 ≤ Will
Maintaining Burden Disadvantage self-control (Bad Temper, Greed, etc.)	3d6 ≤ Will
Resisting Fast-Talk or social manipulation	Contested: Will vs. attacker's skill
Resisting Intimidation	3d6 ≤ Will
Breaking a grapple mentally (willpower overcoming fear of capture)	3d6 ≤ Will at modifier
Enemy morale check (NPC)	3d6 ≤ Will modified by reputation

Will vs. HT for Curse Resistance
Certain curses require HT resistance rolls; others require Will resistance. This is the GURPS distinction between physical afflictions (disease, poison — HT rolls) and mental/magical afflictions (curses, compulsions — Will rolls). Some curses require both — a particularly nasty curse that attacks body and mind simultaneously. Characters who invest only in Will or only in HT will find themselves vulnerable to one category.

Perception (Per)

Default Formula: Per = IQ
Buy-Up Cost: 5 character points per level (GURPS rate)
GURPS Atlas Cost: 4 Skill Points per +1 Per

Perception is the awareness stat — how much the world reveals itself to the character before they have to find it the hard way.

Per Applications:

Situation	Roll
Detecting a Stealthed enemy	Contested: Per vs. enemy Stealth
Noticing a trap before triggering it	3d6 ≤ Per
Detecting buried/hidden treasure	3d6 ≤ Per (modified by distance and concealment)
Weather-reading (upcoming storm)	3d6 ≤ Per (base, before Meteorology skill)
Noticing unusual ship behavior at sea	3d6 ≤ Per
Reading an enemy's tell before an attack	3d6 ≤ Per (enables Danger Sense-like UI hint)

The Treasure Detection System
Per is the primary driver of Salt & Steel's proximity-based treasure detection. The game maintains a hidden list of concealable treasures in every zone. When the player enters a zone, their Per determines:

The detection radius at which the treasure proximity indicator activates (Base: Per meters; e.g., Per 12 = 12m detection radius)
The precision of directional indication (Per 14+: compass-direction indicator; Per 11–13: hemisphere indicator; Per ≤ 10: only activates within 5m regardless)
Whether special treasure (cursed artifacts, legendary items) registers at all (requires Per 13+ to detect magical items beyond mundane proximity)

High Per characters move through the world with a distinctly different information experience — the game presents more of itself to them without being asked.

Basic Speed

Default Formula: (DX + HT) ÷ 4
Buy-Up Cost: 5 character points per +0.25 Speed (GURPS rate)
GURPS Atlas Cost: 3 Skill Points per +0.25 Speed

Basic Speed is the derived stat that most directly represents a character's overall combat tempo. It affects:

Dodge Value: Basic Speed + 3, rounded down to nearest integer
Initiative Order: In simultaneous-resolution encounters (opening moments of combat), higher Basic Speed = acts first
Attack Cadence: Basic Speed feeds the engine's attack animation lockout calculation — higher Speed means shorter minimum intervals between attacks

Speed Calculation Examples:

Character	DX	HT	Basic Speed	Dodge
Navigator	10	10	5.00	8
Buccaneer	10	12	5.50	8
Mariner	10	14	6.00	9
Corsair	14	10	6.00	9
Privateer	12	11	5.75	8
Mystic	10	12	5.50	8

The Corsair and Mariner have the same Dodge despite reaching it by opposite routes — DX (expensive, broad) vs. HT (cheap, narrow). This is a deliberate design: two characters with the same defensive number but completely different builds, one investing in magical and skill breadth, the other in resilience and endurance.

Basic Move

Default Formula: Basic Speed rounded down to nearest integer
Buy-Up Cost: 5 character points per +1 Move (GURPS rate)
GURPS Atlas Cost: 3 Skill Points per +1 Move

Basic Move is the character's movement speed — how many meters they cover per second of real-time movement at standard pace. Sprint speed = Basic Move × 1.2.

Move Impact on Gameplay:

Chase mechanics: characters with higher Move can pursue or flee more effectively
Kiting distance: higher Move creates a larger "safe" range gap when maintaining distance from melee enemies
Boarding speed: Move determines how quickly the character crosses a boarding plank or grapple rope under fire
Naval positioning: in on-deck naval combat, Move governs how quickly the captain can relocate between priority positions

Basic Move is the most directly felt of the secondary stats — the character who moves at Move 5 noticeably shuffles relative to the Move 7 character. This difference is worth communicating visually and in class descriptions.

Dodge

Default Formula: Basic Speed + 3, rounded down
GURPS Atlas Cost: Via Speed nodes or Enhanced Dodge nodes (6 Skill Points per +1 Dodge)

Dodge is the universal active defense — it works against every attack type and requires no specific equipment. Its probability determines how often the player character successfully evades an attack they have manually triggered a dodge response to.

Dodge Probability Table:

Dodge Value	Success Chance	What It Feels Like
6	9.3%	Barely worth trying; mostly a prayer
7	16.2%	Low reliability; better than nothing
8	25.9%	Works sometimes; feels unreliable
9	37.5%	Getting somewhere; still disappointing
10	50.0%	Coin flip; fair but not good
11	62.5%	More often than not; starting to feel reliable
12	74.1%	Good; rare failures feel like bad luck
13	83.8%	Very good; almost always works
14	90.7%	Excellent; failures are notable surprises
15	95.4%	Near-perfect; builds entire identity around evasion

What a 300ms Defense Window Means
The player triggers dodge by pressing the active defense button. The engine then rolls 3d6 against the character's Dodge value. The player's real-time reaction speed determines whether they trigger the dodge at all (inside the window); the character's Dodge value determines whether the triggered dodge succeeds. This is the "two-layer" skill system: player skill gets you to the attempt, character build determines the odds of success.

Parry

Default Formula: ½ weapon skill level + 3, rounded down
GURPS Atlas Cost: Via weapon skill nodes and Enhanced Parry nodes

Parry is the melee weapon active defense — available only when the player has a melee weapon equipped and the attack being defended against is a melee attack.

Parry Probability at Skill Levels:

Weapon Skill	Parry Value	Success Chance
10	8	25.9%
12	9	37.5%
14	10	50.0%
16	11	62.5%
18	12	74.1%
20	13	83.8%

Parry vs. Dodge Decision
Parry is free (costs no FP); Dodge costs 1 FP. This makes Parry more sustainable in extended combat for weapon-equipped characters. However, Dodge works against all attacks (including ranged and magical); Parry only works against melee. The choice of when to Parry vs. when to Dodge is a real tactical decision in sustained combat.

The Blade Saint Keystone improves Parry calculation: Parry = ½ skill + 3 + 1. At Sword skill 20, Parry = 14 (90.7% success) — effectively the same reliability as an excellent Dodge for a melee specialist.

Block

Default Formula: ½ Shield skill + 3, rounded down
GURPS Atlas Cost: Via Shield skill nodes and Enhanced Block nodes

Block is the shield-specific active defense — available only when a shield is equipped. Block works against all melee attacks and most ranged attacks (except those specifically noted as unblockable, such as area-effect explosions).

Block is the "free tank" defense — it costs no FP, it can be used alongside Parry in the same combat turn (though each subsequent defense in the same turn is at cumulative −2), and it provides the solid backbone of the shield-user archetype.

Derived Combat Stats

Damage: Thrust and Swing

Salt & Steel implements the full GURPS damage dice system, scaled by ×10 for ARPG numbers.

The Two Attack Types:

Thrust: The base damage for thrusting attacks (rapiers, boarding pikes, most spears). Formula: see ST table. Lower average than Swing.
Swing: The base damage for swinging attacks (cutlasses, axes, broadswords). Higher average than Thrust. Most melee weapons use Swing for their primary attack mode.

GURPS Damage Table (Salt & Steel ×10 Scale):

ST	Thrust (raw)	Swing (raw)	S&S Thrust avg	S&S Swing avg
8	1d-3	1d-2	10 avg	15 avg
10	1d-2	1d	15 avg	35 avg
12	1d-1	1d+2	20 avg	45 avg
14	1d	2d	35 avg	70 avg
16	1d+2	2d+2	45 avg	80 avg

Averages above are pre-wound-modifier, pre-armor. The actual combat range is wider due to dice variance.

Weapon Damage Modifiers: Weapons add modifiers to the base Thrust or Swing value:

Cutlass: Swing +1 cut (ST 14: 2d+1 cut = ~80 avg × 1.5 wound = 120 avg wound damage)
Rapier: Thrust +2 imp (ST 14: 1d+2 imp = ~55 avg × 2 wound = 110 avg wound damage)
Boarding Axe: Swing +2 cut or Thrust+1 imp (versatile; situational best choice)
Belaying Pin: Swing cr (×1 wound, best knockdown potential)
Flintlock Pistol: 2d pi+ (fixed, not ST-based; 70 avg × 1.5 wound = 105 avg wound damage)

Armor Value (DR — Damage Resistance)

Armor reduces incoming damage by its DR value before wound modifiers are applied:

Penetrating Damage = max(0, Raw Damage − DR)
Final Wound Damage = Penetrating Damage × Wound Modifier

Salt & Steel Armor Types (GURPS Low-Tech adapted):

Armor	DR	Weight	Notes
Clothing only	0	—	No protection; high mobility
Leather Jerkin	1 (10 scaled)	Light	Basic protection; common
Buff Coat	2 (20 scaled)	Light-Medium	Sword-fighter's standard; cuts penalty vs. firearms
Partial Plate (breastplate)	5 (50 scaled)	Heavy	Torso only; ST 12 required
Full Buff + Plate	4 (40 scaled)	Medium-Heavy	Common military officer kit
Heavy Plate	7 (70 scaled)	Very Heavy	ST 14 required; boarding tank gear
Enchanted Armor	Varies	Varies	Magic-enhanced DR; crafted or looted

DR and Damage Type Interaction
Armor DR reduces the raw damage number before the wound multiplier applies. This makes damage type selection meaningful:

A rapier (Thrust +2 imp, ×2 wound) against DR 3 armor:
- Raw damage 5, −3 DR = 2 penetrating, ×2 = 4 final wound damage
A belaying pin (Swing cr, ×1 wound) against the same target:
- Raw damage 8, −3 DR = 5 penetrating, ×1 = 5 final wound damage
At this low penetrating damage range, crushing actually outperforms impaling because it doesn't need multiplier room to work with.

Against heavily armored targets, high damage weapons (Swing-based, Guns) perform better than low-base multiplier weapons. Against unarmored targets, impaling weapons pull ahead dramatically because the ×2 multiplier applies to the full penetrating damage.

The Damage Pipeline

This is the complete sequence from player input to final damage number, running at 60fps in real-time:

1. ATTACK INITIATION
   Player activates attack skill or weapon
   
2. ATTACK ROLL (3d6 ≤ attack skill)
   Engine calls roll3d6() and compares to character's attack skill level
   → If roll > skill: MISS (attack animation plays, no damage)
   → If roll ≤ skill: HIT ATTEMPTED
   
   Margin of Success (MoS) = skill − roll
   (Used for special effects: high MoS = some Ascendancy bonuses trigger)
   
   Critical Success: roll ≤ 4 OR roll ≤ (skill − 10), whichever is more
   Critical Failure: roll ≥ 18 OR roll ≥ (skill + 10), whichever is less
   
3. HIT LOCATION
   Default: Torso (0 modifier)
   Targeted techniques: apply location penalty to attack skill, location modifier to wound
   Engine tracks: which hit location was struck
   
4. ACTIVE DEFENSE WINDOW (300ms real-time window opens)
   Defender may trigger: Dodge (costs 1 FP), Parry (free, weapon must be ready), or Block (free, shield equipped)
   Engine calls roll3d6() and compares to chosen defense value
   → If roll ≤ defense: DEFENDED (no damage; defense animation plays)
   → If roll > defense: DEFENSE FAILS (attack lands)
   
   Note: If no defense input in the window, the attack lands automatically.
   Note: If this is 2nd+ defense in 2 seconds, cumulative −1 per additional defense.
   
5. RAW DAMAGE CALCULATION
   raw_damage = weapon.roll_dice() + weapon.modifier
   (All dice are ×10 scale: "2d" = roll two d6, multiply result by 10, add modifier ×10)
   
   On Critical Success: raw_damage doubled (standard crit), OR special critical effect
   On Normal Success with high MoS: some attack bonuses trigger (Ascendancy-specific)
   
6. DAMAGE TYPE IDENTIFICATION
   weapon.damage_type ∈ {Cutting, Impaling, Crushing, Piercing(size), Burning, Corrosion, Toxic}
   
7. ARMOR PENETRATION
   defender.DR = armor.DR + equipment_bonuses + DR_advantages
   penetrating_damage = max(0, raw_damage − defender.DR)
   
   → If penetrating_damage = 0: ARMOR FULLY ABSORBS (impact effect but no wound)
   
8. HIT LOCATION MODIFIER
   location_multiplier = hit_location.wound_modifier × damage_type.wound_modifier
   
   Example: Impaling attack to Vitals:
   - Impaling base ×2
   - Vitals location ×3
   - Combined: penetrating_damage × 6
   
9. WOUND CALCULATION
   wound_damage = penetrating_damage × location_multiplier
   
10. KNOCKDOWN CHECK
    If wound_damage ≥ (defender.HP / 2):
        engine.roll3d6() vs. defender.HT
        → Fail: target is Knocked Down (prone, stunned, cannot defend for 1 second)
        → Success: target continues, but injury penalty accumulates
        
11. SPECIAL EFFECT APPLICATION
    Cutting: wound_damage > 5 → apply Bleeding (3% of HP per second, 10 seconds)
    Impaling: wound_damage > 5 → deep wound (doubled duration of any applied condition)
    Crushing: + knockdown probability bonus (+25% failure chance on knockdown roll)
    Burning: apply Ignite if damage > 3
    Corrosion: reduce target's armor DR by 1 for this fight
    Toxic: apply Poison stack (1 HP per second, 10 seconds, stacks up to 3)
    
12. FINAL DAMAGE DISPLAY
    Apply wound_damage to defender.HP
    Display floating damage number (color-coded by damage type)
    Update HP bar
    Play appropriate hit animation and audio

This pipeline runs for every attack resolution in the game — player attacks on enemies, enemy attacks on the player, and NPC-on-NPC attacks during boarding actions. The 3d6 rolls at steps 2 and 4 are the heart of the GURPS feel: the bell curve ensuring that skilled characters succeed reliably and unskilled characters fail predictably, without the dramatic streaks of flat-distribution systems.

The Fatigue System

FP is treated elsewhere as the action resource; this section details the full FP simulation and its narrative expression.

FP as the Sea's Toll

Every physical action at sea costs the body something. GURPS models this through FP because the system recognizes that a fight is not just about whether you can win — it is about whether you have anything left after winning. Salt & Steel uses this principle to create the tension of sustained encounters: the player is not just managing hit points; they are managing how much they have to give.

The narrative implication is intentional and reinforced visually and aurally:

FP at 66%: Normal. The captain is working hard.
FP at 50%: The character's movements become slightly more deliberate. Breathing is audible.
FP at 33%: The threshold where the Mariner's "Deep Reserves" Ascendancy ability kicks in. Movement penalties begin. The camera may micro-jitter during intense combat.
FP at 20%: Character voice lines shift — the captain sounds strained. Crowd NPCs react with visible concern.
FP at 10%: Maximum danger. The character's attacks are visibly slower. Dodge animations are desperate.
FP at 0: HP begins draining. The character is burning their body's last resources.

FP Sources

Source	FP Gained	Notes
Rest out of combat (base)	1 per 5 seconds	Standard recovery rate
Rum (consumable)	+3 FP immediately	Also provides brief will boost; Burden: The Bottle requires this
Field Rations (consumable)	+1 FP immediately	Slower, safer, reliable
Crew Resupply (Quartermaster)	+5 FP in Resupply Zone	Requires Quartermaster Ascendancy ability
Fit Advantage (Atlas)	+20% recovery rate	Passive
Tide Caller's Falling Tide state	×2 recovery rate	Cyclical; 45 second window
Spectral Rejuvenation (Necromancer)	+3 FP on kill	Killing marked targets
FP Potions (rare)	+5 FP immediately	Rare drop; not farmable

FP and the Encounter Design Contract

Level designers must account for FP budget when designing encounter sequences. A series of back-to-back fights with no rest opportunity will drain any character's FP — this is a feature, not a bug. The tension of a dungeon's interior comes partly from the player asking: can I reach the end before I run dry?

The intended FP budget for an encounter:

Standard combat room: 5–10 FP average drain for a fully-capable build
Elite/named enemy: 10–20 FP drain
Boss fight: 25–40 FP drain (the boss fight should feel like it is testing your reserves)
Rest point between zones: Full FP recovery available

Characters who invest in HT and FP nodes can extend their effective "dungeon depth" by having larger pools. Characters who invest in FP recovery advantages can replenish faster between rooms. This is the horizontal axis of FP design: not just "do I have enough to win this fight" but "do I have enough to win this fight and still have resources for what comes next."

The 3d6 Bell Curve: Why It Matters

Every roll in Salt & Steel — attacks, defenses, skill checks, curse resistance — uses 3d6 roll-under against a target number. This is not an implementation detail. It is the game's mechanical soul.

The bell curve produces two properties essential to the GURPS-depth fantasy:

1. Skilled Characters Feel Skilled
At skill 14 (90.7% success rate), a character hits nine times out of ten. They do not have a 1-in-20 chance of catastrophically fumbling the way a d20 system produces. Their skill is real — it manifests consistently, not occasionally. The captain who has invested heavily in Broadsword fights with the dependability that investment should produce.

2. Low Skill Feels Appropriately Punishing
At skill 9 (37.5% success rate), the character misses more often than they hit. No lucky streaks will save an unskilled character in a fair fight. The bell curve is unforgiving at the low end — this is correct and intentional. Salt & Steel is not a game where you can randomly succeed at things you are genuinely bad at.

The Crit Expansion at High Skill
The GURPS critical success rule is the system's most dramatic feature:

Skill 14: crits on roll ≤ 4 (0.46%)
Skill 15: crits on roll ≤ 5 (4.6%)
Skill 16: crits on roll ≤ 6 (9.3%)
Skill 18: crits on roll ≤ 8 (25.9%)
Skill 20: crits on roll ≤ 10 (50.0%)

At the pinnacle of skill, half your attacks are critical successes. This is not a broken system — it is the game communicating that mastery means mastery. A pirate with Sword-20 (achievable only through the Blade Saint Keystone and maximum Atlas investment) fights at a qualitatively different level from any common enemy. Their crits are routine. Their misses are news.

This crit expansion is a primary driver of endgame power fantasy: the late-game character who criticals every other attack, triggering Ascendancy effects and dealing massive wound damage, is mechanically expressing the years of investment they have made. That expression is honest — the system earns it.

See Also:
Skill Atlas — how attributes translate into Atlas node costs and stat upgrade paths
Classes and Ascendancies — how class starting distributions express these stats in practice
Leveling and Progression — how stats improve over the character's lifetime
GURPS Adaptation Research — probability tables, damage formulas, and full GURPS source references