Salt & Steel: Skill and Ability System

Document Type: Design Specification — Core Systems
Status: Canonical Draft
Last Updated: 2026-04-24
See Also: Combat System | Movement and Controls | GURPS Adaptation Research | Character Framework

Overview

Salt & Steel's skill and ability system is built on a single organizing principle: abilities are not slots you fill — they are expertise you earn. There are no cooldowns on a bar to cycle through. There is no rotation to memorize. There is only a pirate who has learned to do things through practice, investment, and occasionally a pact with something older than the sea.

Every active combat ability is the mechanical expression of a GURPS skill at a specific mastery level. Every passive benefit is a GURPS advantage purchased through the Skill Atlas. The bell curve governs whether an ability succeeds. The point cost of the Atlas determines how much expertise a character can accumulate. The magic is not in the numbers — it is in who the character has become by the end of character development.

This document describes weapon skills (what your body knows), magical abilities (what forces flow through you), how the two interact, the progression mechanics that deepen both, and the Support Ability system that lets one expertise amplify another.

1. The Skill Atlas

1.1 Architecture

The Skill Atlas is Salt & Steel's passive tree — a spatial map of interconnected nodes representing every GURPS point investment available to a character. It is not a straight line from A to B. It is a map with five major regional clusters, cross-training corridors between them, and keystone nodes at the edges that represent the highest expression of a single domain.

The Atlas is large. No character will ever fill it. That is intentional.

The Five Regions:

The Blade Coast — Combat: melee, ranged, shields, wrestling, dual-wield
The Crow's Nest — Seamanship: navigation, ship handling, rigging, meteorology
The Tide Caller's Circle — Arcane: spell colleges, curse lore, ritual magic, occultism
The Merchant's Tongue — Social: intimidation, persuasion, leadership, tactics
The Survival Shoal — Exploration: stealth, climbing, swimming, first aid, trapping

Characters begin near the center — where the secondary stat nodes (HP, FP, Will, Per) provide universal benefits — and path outward. A pure melee character stays in the Blade Coast; a hybrid pirate-mage crosses the corridor between the Blade Coast and the Tide Caller's Circle; a social-naval specialist develops deep in the Crow's Nest and Merchant's Tongue.

1.2 Node Types

Stat Nodes (1–2 Skill Points): Small increments. +1 to a specific skill level, +5 HP, +2 FP, +1 to a specific attribute fraction. These are the connective tissue of the Atlas — cheap steps between meaningful nodes.

Technique Nodes (2–4 Skill Points): Unlock or reduce the penalty for a specific combat technique (Targeted Attack, Dual-Weapon Attack, Feint, Rapid Strike). These are the nodes that add qualitative new options to existing skills.

Advantage Nodes (4–15 Skill Points): Full GURPS advantages as single purchases. Danger Sense (15 pts), Combat Reflexes (15 pts), High Pain Threshold (10 pts), Ambidexterity (5 pts). These are the nodes that define a character archetype — not just making them better at a thing, but making them someone who does that thing.

Keystone Nodes (8–45 Skill Points, prerequisite chains required): The rarest and most powerful nodes on the Atlas. Each Keystone changes the rules of play in a specific domain. You cannot begin at a Keystone — you must earn your way there through the prerequisite chain. This is not friction; it is the game communicating that Keystones represent extraordinary mastery, not an early-game shortcut.

Burden Nodes (negative value, generate Skill Points): Optional nodes the player may activate by pathing through them. Each Burden represents a GURPS disadvantage the character adopts. Burdens provide bonus Skill Points equal to their disadvantage value. They cannot be deactivated — once the character has "the bottle" or "blood-fever," they have it. Maximum Burden accumulation: −50 points.

1.3 Skill Point Economy

Skill Points are the currency of the Atlas. They are earned through:

Leveling up (primary source, from XP gained by combat, exploration, and quests)
Completing challenges tied to specific skill domains (using a weapon type 500 times unlocks a bonus node in that weapon's cluster)
Voyage-specific rewards
Rare Tome items (grant 1–3 Skill Points directly; craftable and droppable)

Skill Point → Skill Level Cost (Average-difficulty weapon skill, DX 12 base):

Skill Level	Total Points Invested	What Changes at This Level
11 (DX-1)	2 pts	62.5% success rate. Functional but unreliable.
12	4 pts	74.1%. Can hold your own.
13	8 pts	83.8%. More reliable than most opponents will account for.
14	12 pts	90.7%. Parry becomes genuinely defensive.
15	20 pts	95.4%. Mastery Tier 1. First major technique unlock.
16	28 pts	97.7%. Crits at skill−10 = 6 → 9.26% crit rate.
18	50+ pts	99.5%. Crits on 8 or less → 25.9% crit rate. Near-superhuman.

Going beyond skill 16 in most weapon skills requires the Weapon Master keystone (or equivalent) to lift the cap — exactly as PoE's ascendancy keystones unlock power beyond the normal passive tree ceiling.

2. Weapon Skills

2.1 Skill Difficulty and Defaults

Every weapon skill has a GURPS difficulty rating that determines how fast it progresses relative to point investment, and a default value if the skill has not been purchased.

A character who has never held a cutlass still has a default Sword skill (DX−5). They can attempt the skill at this low level — a capable fighter could theoretically pick up any melee weapon and do something with it. But the default is low, success is unreliable, and the character feels the difference.

Defaults create a realistic world: When a character with Sword-15 is disarmed and grabs a boarding axe, they fight at Axe DX−5 (if they have not invested in Axe skill) — suddenly dangerous but not impossible. The weapon skill system makes the player feel the transition.

2.2 The Weapon Skill Families

SWORD (Average / DX-based)

Sub-skills with default relationships:

Shortsword (A): The entry point. Defaults from Broadsword−2 or DX−5.
Broadsword / Cutlass (A): The pirate standard. Defaults from Shortsword−2 or DX−5.
Rapier (A): Specialized for thrusting. Defaults from Broadsword−4 or DX−5. Enables the highest-ceiling impaling damage in the game.
Sabre (A): Combines elements of both. Defaults from Broadsword−2 or DX−5.
Two-Handed Sword (A): Large blades for maximum reach and damage. Defaults from Broadsword−4. Requires both hands; no shield simultaneously.

Mastery Tiers — Sword (example, all weapon skills follow this pattern):

Tier	Skill Level	Unlock
Competent	12–13	Full access to all standard attacks; no technique bonuses
Proficient	14	Parry value becomes reliable combat tool (Parry 10)
Expert	15	Unlock Tier 1 Techniques: Feint, Riposte, basic Targeted Attack
Master	17	Unlock Tier 2 Techniques: Dual Thrust, Cutting Counter, Throat Strike
Grandmaster	19+	Requires Weapon Master keystone; Tier 3 Techniques; Parry at ½+3+bonus

AXE (Average / ST-based)

Hatchet (A): Light one-handed. Can be thrown. Defaults from Axe−3 or DX−5.
Boarding Axe (A): The pirate's multipurpose tool and weapon. Defaults from DX−5.
Great Axe (A): Two-handed. Enormous swing damage. Defaults from Axe−3.

Axes deal more swing damage than swords at equivalent ST. The payoff for Axe investment is raw output against moderate-armor targets. The cost is slightly lower parry efficiency (axes are awkward parrying weapons) and no thrust-impaling option.

POLEARM (Average / DX-based)

Pike / Boarding Pike (A): Reach 1–2. Exceptional against boarding attackers. Defaults from Spear−2 or DX−6.
Halberd / Poleaxe (A): Reach 1–2, cutting or impaling options. Defaults from Polearm−4 or DX−6.
Harpoon (A): Reach 1. Can be thrown. Can pin enemies. Defaults from Spear−2 or DX−5.

Polearms are the specialists' weapons of on-deck combat. A character behind a door with a boarding pike is nearly impossible to approach — reach attacks against enemies in close range suffer no penalty, while the attacker in close range cannot benefit from their own reach weapon. The harpoon adds the unique Pin Technique: a successful impaling hit can pin the target to a surface (deck, mast, wall), immobilizing them until the weapon is removed or the target breaks free (ST vs. ST contest).

SHIELD (Easy / DX-based)

Buckler (E): Smallest, cheapest, strapped to the forearm. One-handed attacks with no penalty. Cannot bash. Defaults from Shield−2 or DX−4.
Round Shield (E): Standard. Can bash (crushing, reach 1). Defaults from DX−4.
Large Shield / Tower Shield (E): Maximum block value and DR coverage. Penalizes movement and attack rolls slightly. Defaults from Shield−2 or DX−4.

Shield skill is unusual — it is Easy (cheapest to buy) and one of the most efficient defensive investments on the Atlas. A character with Shield-12 has Block 9 (37.5% success rate) — adequate. Shield-16 gives Block 11 (83.8%). The Shield cluster on the Atlas makes the block specialist a genuinely different combat archetype: reliable, counter-focused, sustainable over long engagements.

Shield Bash: Using the shield as an offensive tool (Round Shield or larger). Crushing damage (1d−1 for buckler, 1d for round, 1d+1 for large). On a successful bash with margin 3+, apply knockdown check. Shield specialists who invest in the Bash technique create a rhythm of bash-stagger-strike that differs mechanically from any weapon combo.

BRAWLING (Easy / DX-based)

The foundation of unarmed combat. Encompasses punching, headbutting, and defensive grappling.

Brawling (E): Defaults from DX−4. Punch (thrust−1 crushing), kick (thrust crushing, −2 to hit), headbutt.
Wrestling (A): The grappling art. Enables the full grapple/pin/throw system. Defaults from DX−5.
Karate (H): Trained striking. Replaces Brawling punch damage with thrust. Enables the Kiai (combat shout causing stun check) and Spinning Kick techniques.

Brawling and Wrestling are the primary skills for boarding combat — fighting in tight quarters where weapons are awkward. A character with Wrestling-14 can grab an enemy, drag them to the ship's railing, and throw them overboard in three seconds. This is a mechanically complete and viable combat style.

KNIFE (Easy / DX-based)

Knife (E): The universal backup. Concealed, always available. Defaults from DX−4.
Main-Gauche (A): Parrying dagger. Built for the off-hand. Parries as a weapon in the off-hand without penalty. Defaults from Knife−1 or DX−4.
Thrown Knife (E): Separate skill for throwing. Defaults from Knife−3 or DX−4.

Knife and Main-Gauche feed the dual-wield archetype. A character with a cutlass in the main hand and a main-gauche in the off-hand has two parry options (each weapon can parry once per defense window), plus the cutlass's full attack options. This is the classic duelist setup — fast, defensive, and highly reliant on skill because the main-gauche's low damage means the build wins by outlasting opponents, not bursting them down.

PISTOL / FIREARMS (Easy / DX-based)

Pistol (E): Covers all one-handed firearms. Flintlock, wheel-lock, early percussion. Defaults from DX−4.
Long Arm (E): Musket, rifle, blunderbuss. Defaults from Pistol−2 or DX−4.
Hand Cannon (A): Two-handed, heavy. Extreme damage. Defaults from Long Arm−2 or DX−5.

Firearms investment is primarily about reliability and special techniques. At low skill (10–11), firearms miss too often and malfunction too frequently to be reliable — the bell curve makes a Pistol-10 character land shots 50% of the time. At Pistol-15, the firearm is nearly always on target — that 95.4% success rate means shots land, and with the bell curve's crit behavior, Pistol-15 crits on 5 or less (4.6% of shots).

Malfunction (Malf) System: Firearms have a malfunction number (standard: 16–17). A roll of 16+ on the attack roll (even a technically successful roll if skill is 17+) triggers a malfunction check. The player must spend 3 seconds clearing the misfire before the weapon can fire again. The Guns skill node cluster reduces Malf numbers by 1–2 points, improving reliability.

CROSSBOW (Easy / DX-based)

Light Crossbow (E): Faster reload (5 seconds), moderate damage. Defaults from DX−4.
Heavy Crossbow (E): Slower reload (10 seconds), high damage. Defaults from DX−4.
Repeating Crossbow (A): Magazine system. 5 bolts, 2-second cycling between shots, then 20-second reload. Defaults from Crossbow−4.

Crossbows occupy a middle ground between melee and musket: better reload time than firearms, respectable damage, silent operation (no powder report). Characters who invest in crossbow are stealth-viable ranged fighters — the crossbow does not announce their position. The repeating crossbow enables a rapid-fire fantasy that no other ranged weapon in TL5 can provide.

THROWING (Easy / DX-based)

Throwing Knife (E): See Knife.
Thrown Axe (E): A hatchet thrown. Shorter range than knives, more damage.
Grenado / Fire Pot (A): Timed fuses, area effect. Harder skill (requires estimating bounce and detonation). Defaults from DX−5.
Net (A): Entangling, not damaging. Target hit by net must make a DX check or be entangled (movement and attacks at −4 until escaped).

The Throwing skill cluster creates a versatile fighter who supplements melee with ranged harassment. It is not a standalone archetype (damage output is too limited) but is an excellent secondary investment for melee characters who want more engagement options.

TWO-WEAPON FIGHTING (Hard / DX-based)

Not a skill in itself, but a system requiring both weapons to have their own skill AND the following:

Ambidexterity Advantage (5 pts): Removes the −4 off-hand penalty. Without it, both weapons attack at −4.
Two-Weapon Fighting Technique (4 pts per level, 3 levels): Reduces the dual-weapon attack penalty per level (−4 → −3 → −2 → −1 → 0 at max investment combined with Ambidexterity).
Dual-Weapon Attack: The two weapons can target the same enemy (one combined attack at reduced penalty) or split between two enemies.

The dual-wield specialist requires significant Atlas investment — Ambidexterity, both weapon skills at high level, and the Technique nodes — but produces the highest attack frequency of any melee archetype. A cutlass + main-gauche character with Sword-15, Main-Gauche-14, and full Two-Weapon investment can make approximately 1.8 attacks per second while maintaining two parry options per defense window.

3. Magical Abilities

3.1 The Nature of Salt & Steel Magic

Magic in Salt & Steel is not arcane theory. It is relationship with forces older than civilization. The sea has gods — or things that were old before gods had names. The tides keep count. The stars remember. The dead do not rest easily in waters that have no horizon. A pirate who learns to call on these forces is not studying a scholarly discipline; they are entering a conversation with something that may answer in unexpected ways.

This means magic in Salt & Steel is:

Expensive in FP. Spells drain Fatigue Points at rates that make sustained casting feel like running into a headwind. The body pays for what the sea gives.
Unreliable under pressure. Spells are skills — they roll 3d6 like every other action. A mage with Spell skill 14 succeeds 90.7% of the time. A mage with Spell skill 10 succeeds half the time. Panicked casting (under combat conditions without adequate preparation) applies a −2 penalty to spell rolls. Tide Callers take their time, or they risk failure.
Resisted. Hostile spells allow the target a Will check (3d6 ≤ Will) to resist the effect. A Bone Singer cursing an enemy with Will 12 faces a 74.1% resistance rate. They must build their curse skill high enough that even the resistance roll is not certain.
Distinct from weapons. Spells do not benefit from weapon skill nodes. A fighter with Sword-18 who dips into the Tide Caller's Circle starts at Tide Magic Spell skill 9 — they must invest separately or accept that their magic is a weak supplement.

3.2 The Six Magical Traditions

TIDE MAGIC

The oldest magic in these waters. The sea can be asked — and it sometimes answers.

Source: Water, storm, currents, the great depths
Skill Base: IQ (Hard)
FP Cost: 2–8 FP per spell

Representative Spells:

Wave-Call (H, 2 FP): Summon a wave that knocks down all enemies in a 3m line. HT check or knockdown. Range: self.
Fog Weave (H, 3 FP): Create a 10m radius fog bank for 30 seconds. All ranged attacks within −4. Navigation through the fog requires Seamanship check.
Storm-Sight (A, 1 FP): See clearly through weather effects for 60 seconds. Negates all vision-based combat penalties from weather.
Current Pull (H, 4 FP): Slow a single target as though walking against a current — movement halved, attacks at −1. Lasts 10 seconds. Will resist.
Maelstrom (VH, 8 FP): The signature high-level Tide spell. A 5m vortex that pulls all enemies toward its center, dealing crushing damage and knockdown. 5-second channel; visible wind-up; devastating if it lands.
Walk the Deep (VH, 6 FP): The character can breathe water and move freely underwater for 5 minutes. No swimming penalties. Useful for underwater exploration and ambushing ships from below.

Tide Magic Keystone — "Caller of the Deep": All Tide Magic spells cost 25% less FP. The character's presence at sea generates a passive aura — enemies within 5m are slightly slowed (as though in shallow water). The sea knows you.

FLAME ARTS

Fire loves destruction. So does a proper pirate.

Source: Combustion, chemical reaction, controlled chaos
Skill Base: IQ (Hard)
FP Cost: 2–7 FP per spell

Flame Arts is the most immediately useful magical tradition in direct combat — its spells deal reliable burning damage and create area denial that no other tradition matches.

Representative Spells:

Torch (E, 1 FP): Ignite a weapon or object. Adds 1d burning damage to weapon attacks for 60 seconds. The cheapest magical augmentation in the game.
Flash Powder (A, 2 FP): Directed flash of light. Stuns all targets in a 3m cone who fail a HT check. 0.5-second stun duration. Excellent crowd control.
Alchemist's Fire (H, 4 FP): Throw a bolt of sustained fire. Deals 2d burning damage; target must make a HT check or be Alight for 5 seconds. Range: 20m.
Hot Shot (H, 3 FP): Enchant a cannonball or musket ball to be Heated — if it penetrates, it starts a fire at the impact point. Extremely useful in naval combat (Hot Shot cannon = fire on enemy ship).
Conflagration (VH, 7 FP): The high-level Flame spell. Explosive burst in a 4m radius, dealing 3d burning damage to all targets. Ignites everything flammable. Sets the ground alight (zone damage) for 10 seconds.

Flame Arts Keystone — "Burning Powder": All Flame Arts spells add 1 burning damage die per 5 levels of Flame Arts skill above 12. A Flame Arts-17 character's Conflagration deals 4d instead of 3d. The character's weapon attacks have a 15% chance to deal 1d bonus burning damage on hit — uncontrolled, ambient heat.

SHADOW WEAVING

Not darkness. Not absence. Presence — the presence of the thing in the dark.

Source: Shadow, fear, misdirection, the spaces between
Skill Base: IQ (Hard)
FP Cost: 1–6 FP per spell

Shadow Weaving is the stealth and disruption tradition. Its spells rarely deal direct damage — they manipulate perception, fear, and attention. In the hands of a skilled practitioner, enemies fight each other, flee from nothing, or simply fail to notice the knife at their throat.

Representative Spells:

Veil (A, 1 FP): The character becomes difficult to see clearly — attackers at −2 to hit for 30 seconds. Not invisibility; a subtle wrongness in the light.
Phantom Step (H, 2 FP): The character's footsteps are inaudible for 10 seconds. In stealth contexts, automatically beats Per-based detection for sound.
Dread Touch (H, 3 FP): A physical attack that, on hit, adds 2 Dread stacks to the target. Against already-frightened enemies, triggers an immediate Will check or they flee.
Mirror Image (H, 4 FP): Create two illusory duplicates of the character. Enemies must make a Per check to attack the real character — 1-in-3 chance per attack. Lasts 20 seconds or until both illusions are destroyed.
Heart Fear (VH, 6 FP): The high-level Shadow spell. A targeted fear effect with no physical component — pure psychic assault. The target must make a Will check at −4 or be Frighted (fleeing, combat-incapable) for 5 seconds. Even on a save, the target is at −2 Will and −2 all combat rolls for 15 seconds.

Shadow Weaving Keystone — "Thing in the Dark": The character can activate a 10-second perfect invisibility (broken only by attacking or being hit) once every 90 seconds. Stealth-based attacks from invisibility gain +4 to attack roll and automatically target the rear arc (bypassing Active Defenses entirely). The character cannot be detected by sound while Veil is active.

BONE SINGING

The sea takes everything. Bone Singing is about what the sea took.

Source: Death, bones, the unquiet drowned, old curses
Skill Base: IQ (Very Hard)
FP Cost: 3–10 FP per spell

Bone Singing is Very Hard — expensive on the Atlas and slow to master. Its power justifies the cost. At high skill levels, a Bone Singer commands the dead as crew, curses living enemies with persistent debilitating effects, and channels the cold of the deep as a damage source that ignores all physical armor.

Representative Spells:

Cold Grasp (H, 3 FP): Supernatural cold damage (bypasses DR) in a melee strike extension — the attack becomes a touching cold reach to range 1. 1d+2 supernatural damage.
Wail of the Drowned (H, 4 FP): An eerie sound that forces all enemies within 8m to make a Will check at −2 or gain 3 Dread stacks instantly. On a Frighted result, enemies drop their weapons.
Raise Drowned (VH, 6 FP): Animate a recently-dead humanoid as a Drowned Crewman under the character's command. The drowned has the dead character's combat skills at −4, is immune to morale effects, and acts for 5 minutes or until destroyed. Only one drowned can be active at a time (without the advanced keystone).
Black Curse (VH, 8 FP): Place a complex debuff on a target — choose from: −4 to all combat rolls (Inept Curse), halved HP recovery (Wound Curse), or movement halved (Lame Curse). Lasts until removed by magic (Curse-Breaker ability) or the target rests for 10 minutes. Will resist at −2.
Void of the Deep (VH, 10 FP): The high-level Bone Singing spell. A 6m radius zone of supernatural cold. All enemies inside take 2d supernatural damage per second, are at −3 to all rolls, and cannot benefit from FP recovery for the duration (15 seconds). The most powerful sustained-damage spell in the game.

Bone Singing Keystone — "Voice of the Drowned Fleet": The character can have up to three Drowned Crewmen active simultaneously (instead of one). The Drowned gain the captain's Leadership skill bonus as a morale-equivalent. Each Drowned destroyed triggers a free Cold Grasp at the character's full skill against the enemy that destroyed it.

STAR READING

The stars have been watching. You learn to look back.

Source: Celestial positions, fate, probability, divine attention
Skill Base: IQ (Hard)
FP Cost: 2–5 FP per spell

Star Reading is the support tradition. It does not deal damage or move enemies. It amplifies allies, alters probability, and occasionally reveals what is coming before it arrives. A Star Reader in a crew of pirates is not a warrior — they are the reason everything goes right.

Representative Spells:

Favorable Wind (A, 2 FP): For the next 60 seconds, the character and allies within 10m gain +1 to all skill rolls. The stars turn favorable for this little while.
Doom Reading (H, 3 FP): Read the currents of fate around a target. Reveals the target's current HP, their highest skill, and one of their active advantages. Useful intelligence for a difficult fight.
Luck-Bending (H, 4 FP): Once in the next 30 seconds, the character may force a reroll on any one roll (their own or an enemy's) and take either result. This is the mechanical implementation of GURPS Luck — the ability to bend probability.
True Strike (H, 3 FP): The next attack made by the character or one designated ally within 10m is made as though the attacker has +4 to their skill. The stars align for this strike.
Fate Seal (VH, 5 FP): Lock a target's fate at a specific moment — they cannot critically succeed on any roll for 15 seconds. Their attacks and defenses work, but never exceed the normal. Bosses at max effectiveness become reliable instead of terrifying.

Star Reading Keystone — "Chart of the Unwrit": The character gains a passive "fate budget" — once per minute, they may reroll any die result (including enemy critical successes against them) and take the better result. This is always active, requires no FP, and stacks with Luck-Bending. Star Readers become the ultimate reliability architects — the builds where nothing goes catastrophically wrong.

BLOOD BINDING

Power has to come from somewhere. Blood Binding says: take it from yourself.

Source: Life force, sacrifice, berserker discipline, the body's own heat
Skill Base: HT (Hard) — unique; the body, not the mind, governs this tradition

Blood Binding is dangerous. Every spell costs not just FP but HP — the magic literally draws on the body's vitality. In exchange, Blood Binding produces the most powerful direct combat effects of any tradition: physical enhancement, self-repair, and the terrifying berserker state.

Representative Spells:

Blood Surge (A, 2 FP + 5 HP): Enhance the character's combat capabilities — +2 to all attack rolls, +1 die of damage to all melee attacks, lasts 30 seconds. The body pays in blood for the power.
Battlefield Leech (H, 3 FP + 5 HP): The character leeches vitality from the next kill within 10 seconds — recovering 10 HP upon the kill. Combining this with an all-out assault creates a "spend HP for power, kill to recover HP" loop.
Iron Will (H, 2 FP + 3 HP): The character ignores all wound penalties and stun effects for 15 seconds. They fight at full effectiveness regardless of injury. Useful when crippled and pressed.
Berserker State (VH, 5 FP): Activate through Blood Binding. For 20 seconds: all damage dealt +2 dice; all attacks gain +3; cannot use any active defense except block; HP drains at 3 per second. The character is a whirlwind of violence who is also dying while doing it. The ultimate high-risk ability.
Blood Mending (VH, 3 FP + 10 HP): Convert excessive HP cost into healing for allies — heal a touched ally for 15 HP. Sacrifice yourself to save your crew.

Blood Binding Keystone — "Pact of the Red Sea": Blood Surge, Iron Will, and Berserker State have their HP costs halved. The character gains an innate "Death's Door" resilience — at 1 HP, they automatically activate a 5-second Blood Surge (even if already active, it refreshes) before dying. They cannot die during this 5-second window. After it expires, they die normally.

4. Ability Progression

4.1 Practice XP

Using a skill earns Practice XP toward that skill's next mastery tier. Practice XP accumulates in the background — the player does not manually track it; they simply see the Mastery Tier bar filling as they fight.

Practice XP Sources:

Successful attack with a weapon skill: 1 XP per hit
Successful defense with a weapon skill (parry): 1 XP per parry
Spell successfully cast in combat: 2 XP (magic practice requires real pressure to develop)
Using a skill against a significantly stronger opponent (skill 3+ above theirs): 2× XP
Using a skill against a significantly weaker opponent: 0.5× XP (practicing on easy targets builds less)

Why This Matters: The Practice XP system means characters naturally deepen their competence in what they actually use. A player who fights with a rapier every combat and never picks up an axe will become a rapier specialist even if they have points allocated to Axe on the Atlas. The Atlas defines the ceiling; practice determines where within that ceiling the character actually operates.

4.2 Mastery Tiers

Each weapon skill and magical tradition has four Mastery Tiers, reached through Atlas investment AND Practice XP:

Tier 0 — Initiate: The character has the skill at default or very low level (9–11). They can use the weapon but inconsistently. No special techniques.

Tier 1 — Proficient (skill 12–14): The skill is functional and reliable in basic use. Tier 1 Techniques become available:

Weapon-specific bonus (e.g., Sword T1: +1 riposte window duration)
FP cost reduction on associated defenses (−0.1 FP per defense type)
First cosmetic animation upgrade (the character's stances become more confident)

Tier 2 — Expert (skill 15–17): The skill is combat-defining. Tier 2 Techniques unlock:

Signature move (e.g., Sword T2: Cross Counter — parry immediately followed by a counter-thrust at +2 to hit)
Advanced technique access (Targeted Attack techniques at reduced penalty)
FP cost further reduced (−0.25 FP per defense type)
Visual upgrade: weapon effects (glints, motion trails), character animations evolve

Tier 3 — Master (skill 18+, requires Keystone): The character is extraordinary. Tier 3 Techniques:

Weapon-defining ability (e.g., Sword T3: Blade Saint's Parry — parrying a melee attack allows a simultaneous counter at no action cost)
All techniques from Tiers 1–2 enhanced (reduced FP, improved margin requirements)
Passive field effect (e.g., Sword T3 passive: enemies within 3m who have been hit by the character in the last 5 seconds suffer −1 to attack rolls — they have seen what the character can do)
Full visual transformation: the weapon and character visual language announces mastery

4.3 Cross-Skill Synergies (Support Abilities)

Support Abilities are nodes on the Skill Atlas that modify other abilities — a layer of build customization that allows one skill's investment to amplify another. They are the closest analog to PoE's support gem system, adapted for a character who owns their abilities rather than socketing them.

Chain Shot (Throwing + Pistol synergy): Unlocked through both Throwing (12) and Pistol (12) investment. Grenado-type thrown weapons now "trigger" on explosion within 5m of a firearm shot that hits an enemy — the pistol shot hits first, the enemy staggers, the grenade throws itself on automatic. Combines two separate skills into one devastating combo.

Poisoned Edge (Alchemy + Knife/Sword synergy): Unlocked through the Survival Shoal's Alchemy node and any Blade skill at 13+. The character can apply poison to their blade before combat (10-second ritual, one dose per combat). Successful blade hits apply Toxic damage (×1 wound modifier, bypasses DR, stacks) for 15 seconds.

Thunder Strike (Tide Magic + Polearm synergy): Unlocked through Tide Magic-13 and Polearm-13. The character can spend 2 FP to channel a wave of force through a polearm strike — the weapon attack becomes an AoE knockback, pushing all enemies within 2m of the target backward 2m and applying a knockdown check.

Sea Legs Shooter (Seamanship + Pistol synergy): Unlocked through Seamanship-13 and Pistol-13. The character ignores all ship-motion penalties to ranged combat and can fire while sprinting at no attack penalty. Seamanship expertise translates directly into stable combat platform awareness.

Berserker's Parry (Blood Binding + Brawling synergy): Unlocked through Blood Binding-13 and Brawling-13. While Blood Surge is active, the character's successful parries deal 1d crushing bonus damage back to the attacker — the amplified body redirects force through the parry back into the attacker.

5. The Keystone Nodes

Keystones are the Atlas's most powerful and most expensive nodes. Each requires a substantial prerequisite chain, costs 15–45 Skill Points, and changes the fundamental rules of play in one domain.

5.1 Blade Coast Keystones

"Blade Saint" — Weapon Master (Blades)
Cost: 45 pts | Prerequisite: Sword-15, Expert Tier in any Blade skill
Effect: Parry value is recalculated at full skill / 2 + 3 (instead of the standard ½+3 with no bonus). All blade techniques operate as though the skill were 2 points higher for technique penalty reduction. Blade skill may now advance beyond 16 through Practice XP (without this keystone, the standard cap is 16).
Identity: The dedicated swordsperson. One weapon, perfected.

"Dead Eye" — Gunslinger
Cost: 25 pts | Prerequisite: Pistol-14, 200 total firearm shots fired
Effect: No accuracy penalty for firing from movement. No aiming turns required for accuracy bonus. All firearm reload times halved. Malfunction number reduced by 2.
Identity: The pistoleer who shoots like it costs nothing.

"Two-Fisted Devil" — Ambidexterity
Cost: 5 pts | Prerequisite: Two-Weapon Fighting Technique Level 1
Effect: No off-hand penalty. Full dual-wield without Atlas investment in penalty reduction techniques.
Identity: The gateway to the dual-wield archetype. Required before investing further.

"The Untouchable" — Enhanced Dodge 3 + Enhanced Parry 3
Cost: 45 pts | Prerequisite: Dodge-10 (natural), Parry-12 (any weapon), FP 18+
Effect: +3 to Dodge; +3 to Parry with equipped weapon. Cannot use All-Out Attack while this keystone is active.
Identity: The defensive specialist who simply cannot be hit. Their offense suffers; their survival is near-guaranteed. A different relationship with combat.

5.2 Tide Caller's Circle Keystones

"Threshold Mage" — Threshold Magic System
Cost: 35 pts | Prerequisite: Two different spell traditions at skill 13+, 50 FP spent on spells
Effect: All spells cost 50% less FP. However, each spell cast accumulates Threshold Charge. At 30 Threshold Charge, the next spell triggers an Overflow: random catastrophic effect from the Overflow table (additional damage, unintended area effect, FP burn, or a supernatural manifestation). The Threshold resets to 0 after Overflow.
Identity: The high-power mage who dances near catastrophe. Maximum output, genuine risk.

"Curse-Breaker" — Ritual Countermagic
Cost: 25 pts | Prerequisite: Bone Singing-12, Occultism-12, IQ 13+
Effect: The character can perform a 30-second ritual to remove any magical curse or persistent debuff from themselves or an ally. Can also remove environmental Curse effects (cursed treasure, haunted locations). The ritual requires complete concentration (cannot be in combat).
Identity: The party utility specialist. Someone has to be able to fix what the sea breaks.

5.3 Universal Keystones

"Powder-Quick Reflexes" — Combat Reflexes
Cost: 15 pts | Prerequisite: Accessible from first major Atlas branch
Effect: Cannot be surprised. Always acts in the first defense window. +1 to all active defenses. Fast-Draw skill effectively at +6 for initiative purposes.
Identity: The pirate who was born to this.

"Iron Constitution" — High Pain Threshold
Cost: 10 pts | Prerequisite: HT 11+
Effect: All wound penalties are delayed by two injury levels (minor wounds cause no penalty; major wounds apply minor penalties; only severe wounds apply standard GURPS injury penalties). Stun duration halved. No automatic stumble from any single hit below 50% of max HP.
Identity: The character who keeps going when everyone else has fallen.

"Buccaneer's Fortune" — Luck
Cost: 15 pts | Prerequisite: None (accessible from center of Atlas)
Effect: Once per 60 seconds, any die roll may be rerolled. Take the better result. This applies to attack rolls, defense rolls, or any skill check.
Identity: The pirate the universe inexplicably favors.

"Sea Legs" — Perfect Balance
Cost: 15 pts | Prerequisite: Seamanship-12 or Acrobatics-12
Effect: Immune to all ship-motion combat penalties. Immune to knockback from environmental sources (waves, explosions, wind). Immune to Off-Balance condition from environmental triggers. Still vulnerable to knockdown from high-damage hits.
Identity: The sailor who has never fallen on a deck in their life.

6. The Burden System

6.1 Choosing Your Character's Flaws

Burden nodes are optional — the character never encounters them accidentally. They appear as clearly-marked divergences on Atlas paths; the player must consciously path through them and activate them. Once activated, they cannot be deactivated.

Burdens are GURPS disadvantages converted to gameplay mechanics. They make the character more interesting, not weaker. A character with "Blood-Fever" is not a worse character — they are a character with a specific, distinctive relationship with violence that creates different gameplay moments.

6.2 Burden Catalogue

"The Bottle" — Dependency (Rum)
Value: +5 Skill Points
Effect: If the character has not consumed Rum within the last 20 minutes of gameplay, FP regeneration is halved. A single Rum removes this penalty for 20 minutes. Rum is always available (sold at ports, found in most locations) but occasionally scarce at sea between ports.
Gameplay: The Bottle creates a light consumable dependency that the player manages as part of their exploration rhythm. It is a tax, not a punishment — and Rum's FP penalty at high quantities creates an interesting risk/reward.

"Blood-Fever" — Bloodlust
Value: +5 Skill Points
Effect: The character cannot accept an enemy's surrender or voluntarily spare a downed enemy. If an enemy yields, a Will check (3d6 ≤ Will) is required to stop the attack. Failure means the character kills the enemy. Affects reputation in specific ways (Ferocity increases faster; Honor increases slower).
Gameplay: For players who were going to kill everyone anyway, Blood-Fever is purely positive. For players who want to use surrender mechanics for prisoners, it creates dramatic moments of self-control.

"Gold-Sickness" — Greed
Value: +5 Skill Points
Effect: When significant treasure is visible (chest, enemy drop, hidden cache), the character must pass a Will check to leave it unlooted. Failure means they must loot it even if tactically inadvisable. The character also receives −1 to all Merchant rolls when attempting to sell at below-maximum price.
Gameplay: Gold-Sickness creates the "one more chest" mentality as a genuine mechanical compulsion. In dungeons with trapped chests or enemy-surrounded caches, the Will check becomes the tense moment where character gets in character's own way.

"The Mark of Davy Jones" — Cursed
Value: +15 Skill Points
Effect: Every 10–15 minutes of real gameplay, a random minor catastrophe occurs: weapon breaks (durability to minimum), rope snaps at an inopportune moment, a random piece of equipped gear temporarily reduces its stats by 25%, or a crew member develops a temporary grievance. These events are cosmically bad luck, not combat-threatening — they are inconveniences with narrative flavor.
Gameplay: The most expensive Burden for a reason. The Mark creates the experience of playing a character the universe is actively against. Players who build Buccaneer's Fortune (Luck keystone) alongside the Mark create the fascinating combo character the sea both hates and inexplicably protects.

"Glass Eye" — One Eye
Value: +5 Skill Points
Effect: −1 to all ranged attack rolls. −1 to Perception-based skill checks that rely on vision. The character has the cosmetic visual of an eyepatch, glass eye, or scarred socket.
Gameplay: For melee-focused characters, Glass Eye is essentially free points — the ranged penalty is irrelevant. For hybrid fighters who use occasional firearms, the −1 is a genuine trade that requires them to invest more in Pistol skill to compensate.

"Seeing Red" — Berserk
Value: +10 Skill Points
Effect: When the character takes more than 20% of their maximum HP in a single hit, they must pass a Will check or enter Berserk mode: +2 to all attack rolls, −2 to all defense rolls, cannot retreat, and will attack the nearest hostile until all are dead or the character's HP drops below 20% total. Berserk mode lasts at minimum 15 seconds once triggered.
Gameplay: Seeing Red is best paired with the Blood Binding tradition — the Berserker's Parry support ability synergy creates a character who actively wants to trigger Berserk mode and designed their FP/HP economy accordingly. A designed drawback that becomes a designed strength.

7. Internal Consistency Rules

The following rules exist to ensure the skill system never produces contradictory or broken states:

One Active Keystone Rule: Keystones that directly contradict each other cannot both be active. "The Untouchable" (no All-Out Attack) and "Twin Fury" (special All-Out Attack double-hit) cannot coexist on the same character. The Atlas paths are designed so these keystones are in different regions with no connecting path — the player would have to actively path around both sides to reach them, which is detectable and preventable.

Burden Cap: Maximum −50 Skill Points of Burdens on any character. This prevents characters who are so mechanically impaired by disadvantages that they are not fun to play, while allowing players to flavor their character meaningfully.

Magical Tradition Depth Rule: To invest in a second magical tradition beyond skill 12, the first tradition must already be at skill 14+. This prevents broad-shallow magical dips that dilute the identity of magical specialization. A little Tide Magic and a little Flame Arts produces weak versions of both — but mastering Tide Magic first, then expanding, creates a meaningful hybrid with a clear foundation.

Practice XP and Atlas Synergy: Practice XP cannot advance a skill beyond what the Atlas supports. If a character has Sword atlas nodes up to skill 14 but has not purchased the next tier, Practice XP stalls at 99% toward tier 2 until the Atlas investment is made. Practice and investment are parallel requirements — neither alone is sufficient.

See Also:
Combat System — How skills are applied in real-time combat
Movement and Controls — Control scheme for executing skills
Naval Combat — How naval skills apply at sea
Character Framework — Attribute system and point-buy foundation
GURPS Adaptation Research — Probability tables and mechanical foundation