Core Rules

When a character attempts something dangerous, uncertain, opposed, or meaningful, roll:

d20 + Attribute Modifier + Proficiency Bonus, if proficient

Use this for climbing ruined hab-blocks, forcing open bulkheads, interrogating prisoners, repairing broken machinery, resisting fear, firing a lasgun, commanding troops, or staring into something from the Warp without blinking first.

If the result equals or exceeds the target number, the character succeeds.

Bolt & Blade uses six attributes. Each attribute has a Score and a Modifier.

The Score represents the character's raw capability. The Modifier is the number added to most rolls.

Attribute modifiers follow the familiar d20 scale.

Most mortal characters operate in the 8–18 range. Transhuman, monstrous, daemonic, or heavily augmented beings may exceed normal limits.

Proficiencies represent training, experience, instinct, and institutional conditioning.

If a character is proficient in the relevant field, add their Proficiency Bonus to the roll.

A proficiency is not locked to one attribute. The GM chooses the attribute and proficiency that best match the action.

Examples:

• Strength + Athletics to force open a bulkhead.
• Agility + Athletics to leap across a collapsing gantry.
• Intellect + Tech to bypass a cogitator lock.
• Willpower + Awareness to notice a daemonic whisper in the vox.
• Presence + Command to rally terrified militia.
• Intellect + Lore to identify a forbidden sigil.
• Presence + Guile to lie to an officer.
• Intellect + Guile to plan a false identity.

A character's Proficiency Bonus is based on level.

Proficiency Bonus applies to trained checks, certain saves, attacks with trained weapons, and class features that call for it.

When there is no opposing creature, the GM sets a Difficulty Class, or DC.

Use lower DCs when failure would only slow the scene down. Use higher DCs when the action is dangerous, rushed, opposed by hostile conditions, or performed under fire.

Bolt & Blade characters are competent. The grimdark tone should come from stakes and consequences, not from making trained characters fail routine tasks constantly.

When circumstances strongly favor a character, they have Advantage. When circumstances strongly hinder a character, they have Disadvantage.

• With Advantage, roll two d20s and use the higher result.
• With Disadvantage, roll two d20s and use the lower result.
• If both apply, they cancel out.

Examples of Advantage

• Attacking from ambush.
• Having the right tool for the job.
• Acting with strong leverage in a conversation.
• Taking time to aim or prepare.
• Using a relevant class feature.

Examples of Disadvantage

• Acting while blinded, panicked, pinned, or badly wounded.
• Shooting through smoke or darkness.
• Working with damaged tools.
• Trying to lie while visibly corrupted.
• Acting under daemonic pressure.

A check is used when a character attempts an uncertain action. Roll:

d20 + Attribute Modifier + Proficiency Bonus, if proficient

Examples:

• Break a rusted hatch: Strength + Athletics
• Sneak past sentries: Agility + Stealth
• Track cultists through ash wastes: Willpower + Fieldcraft
• Decode a machine shrine: Intellect + Tech
• Search a crime scene: Intellect + Inquiry
• Command panicking civilians: Presence + Command

If the result meets or exceeds the DC, the character succeeds.

A save is used when a character resists danger. Roll:

d20 + Attribute Save Bonus

Each attribute can be used as a save. Examples:

Strength Save. Resist being dragged, crushed, or knocked prone.

Agility Save. Dodge explosions, traps, flamers, or falling debris.

Toughness Save. Resist poison, disease, exhaustion, radiation, or massive trauma.

Intellect Save. Resist mental overload, logic traps, false memories, or machine intrusion.

Willpower Save. Resist fear, corruption, possession, psychic attack, or daemonic influence.

Presence Save. Resist humiliation, domination, social pressure, or supernatural despair.

A character's save bonus may include attribute modifier, proficiency, class features, race/path traits, wargear, or other bonuses.

An attack roll is used when a character attempts to hit a target. Roll:

d20 + Attack Bonus vs. target Defense

If the attack roll equals or exceeds the target's Defense, the attack hits.

Most ranged attacks use Agility. Most melee attacks use Strength. Some weapons, powers, features, or wargear may use a different attribute.

Detailed combat rules, including cover, suppression, reactions, and special weapon traits, belong in the Combat chapter.

Defense is the number an attacker must meet or beat to hit a character.

Defense may come from:

• Armor
• Agility
• Cover
• Shields
• Wargear
• Class features
• Race/path traits
• Psychic powers
• Environmental conditions

A character in the open is easier to kill. A character in cover has a chance. A character in power armor is a walking problem.

Vitality measures a character's ability to keep fighting. It represents stamina, pain tolerance, minor wounds, armor deflection, battlefield positioning, luck, and sheer refusal to die.

At 0 Vitality, a character is down and in danger. They may be dying, unconscious, bleeding out, pinned under rubble, or otherwise unable to continue without aid, Fate, class features, or desperate intervention.

Detailed death, injury, and recovery rules belong in the Wounds, Scars & Death chapter.

When two characters directly oppose each other, both roll. Each side rolls:

d20 + Attribute Modifier + Proficiency Bonus, if proficient

The higher result wins. Examples:

• A prisoner lies with Presence + Guile against an interrogator's Willpower + Inquiry.
• A cultist hides with Agility + Stealth against a guardsman's Willpower + Awareness.
• Two warriors grapple using Strength + Athletics.
• A tech-adept races a hostile machine spirit with Intellect + Tech.

If the result is a tie, the situation remains unresolved, or the side with the stronger position holds. The GM decides based on the scene.

A ranged weapon's Range is written as Normal Range / Maximum Range.

For example, 40/120 means the weapon attacks normally within 40 feet, attacks with Disadvantage from 41 to 120 feet, and cannot attack beyond 120 feet.

A natural 20 is a roll where the d20 shows 20 before modifiers.

On an attack roll, a natural 20 is a Critical Hit. For a Critical Hit:

Roll the weapon's damage dice twice, then add modifiers once.

Some weapons or features may add additional effects on a Critical Hit.

On a check or save, a natural 20 is not always an automatic success, but it should usually produce the best possible outcome if success is plausible.

A natural 1 is a roll where the d20 shows 1 before modifiers.

On an attack roll, a natural 1 misses. Some dangerous weapons, unstable powers, corrupted relics, or damaged gear may trigger additional consequences on a natural 1.

Examples:

• Plasma overheats.
• A psychic power risks Perils.
• A corrupted relic lashes back.
• A damaged weapon jams.
• A stealth attempt makes noise at the worst possible time.

On a check or save, a natural 1 is not always an automatic failure, but it should usually invite a complication when the situation is dangerous.

During structured time, such as combat or high-pressure scenes, characters act in turns.

On your turn, you normally have:

• Movement
• One Action
• One Bonus Action, if you have an ability that uses it
• One Reaction, usable once per round
• Brief speech or interaction

Common actions include:

• Attack
• Dash
• Disengage
• Take Cover
• Aim
• Suppress
• Use Wargear
• Use Power
• Help
• Search
• Ready
• Interact

The Combat chapter will define these actions in detail.

Languages determine what a character can speak, read, understand, or decode. Creed defines the belief, oath, doctrine, machine-cult logic, chapter tradition, or private heresy that shaped them.

Languages and Creed rarely require rolls by themselves. Instead, they decide what information is available, who trusts the character, what rituals they recognize, and what dangers they should have known better than to read aloud.

Both are chosen in the character creator: defaults come from your Race / Path, suggestions come from your class, and hidden or forbidden choices may create suspicion, corruption risk, or faction consequences at the GM's discretion.

The core rules stay simple on purpose. Combat can become more tactical later without changing the foundation.

For Bolt & Blade, the Combat chapter should explore:

• Cover and exposure
• Suppression
• Reactions
• Return fire
• Overwatch
• Movement through killzones
• Opposed combat exchanges
• Dangerous weapon traits

Infinity-style ideas like reactive fire and opposed exchanges are being considered for the Combat chapter, but they should live in Combat rules, not the Core Rules chapter.

The systems that build on this foundation: