Core Rules

This chapter covers the fundamental mechanics of Horizon.

The Four Stats

Every character has four core stats. These values directly represent your modifier (no separate ability score/modifier split).

Typical Values: -1 to +5. Starting characters distribute +2, +1, +1, +0 among their stats.

Rolling Dice

Basic Rolls

When you attempt something with an uncertain outcome:

1. Roll a d20
2. Add your relevant stat modifier
3. Add your proficiency bonus (+2) if applicable
4. Compare to the target number (Difficulty Class or Defense)

Success: Total ≥ target number Failure: Total < target number

Advantage and Disadvantage

Sometimes circumstances make success more or less likely:

• Advantage: Roll 2d20 and take the higher result
• Disadvantage: Roll 2d20 and take the lower result

If you have both advantage and disadvantage, they cancel out regardless of how many of each you have.

Critical Results

Special outcomes occur on natural die results:

Note: Characters with mastery in a domain treat natural 1s as regular failures instead of critical failures.

Skill Checks

The 15 Skills

Skills are grouped by their governing stat:

Might Skills

• Athletics: Climbing, swimming, jumping, feats of strength
• Intimidation: Frightening or coercing through presence
• Endurance: Resisting hardship, holding breath, forced march

Finesse Skills

• Acrobatics: Balance, tumbling, aerial maneuvers
• Stealth: Moving unseen, hiding, ambushes
• Sleight of Hand: Pickpocketing, lockpicking, prestidigitation
• Riding: Controlling mounts and vehicles

Insight Skills

• Perception: Noticing details, spotting hidden threats
• Medicine: Treating wounds, diagnosing illness, stabilizing dying
• Survival: Tracking, foraging, navigation, weather prediction
• Empathy: Reading emotions, detecting lies, understanding motives

Cunning Skills

• Arcana: Magic knowledge, identifying spells and phenomena
• History: Past events, cultures, famous figures
• Investigation: Analyzing clues, deduction, solving puzzles
• Persuasion: Logic, charm, negotiation, rhetoric

Making Skill Checks

d20 + stat modifier + proficiency bonus (if proficient) vs DC

Difficulty Classes

Tiered Success

Not all successes are equal. The margin (how much you beat the DC by) determines the quality:

Complications (GM chooses one for partial success):

• Takes longer than expected
• Attracts unwanted attention
• Costs something (item damaged, resource spent)
• Creates a new problem
• Achieves a lesser version of your goal

Contested Checks

When two characters oppose each other directly:

1. Both roll their relevant skill check
2. Higher total wins
3. Ties go to the initiator (whoever started the contest)

Proficiency

Proficiency Bonus: +2 (this never changes)

You add your proficiency bonus when:

• Making a check with a skill you’re proficient in
• Making an attack with a weapon you’re proficient with
• Making a saving throw you’re proficient in
• Casting spells (if you have spellcasting ability)

Proficiencies come from your Path, background, and talents.

Health Points (HP)

HP represents your ability to avoid and absorb damage.

Starting HP = Hit die maximum + Might modifier (minimum 1)

HP Per Level = Hit die average + Might modifier (minimum 1)

Defense

Defense determines how hard you are to hit in combat.

Defense = 10 + Armor Bonus + Finesse Modifier (limited by armor type)

Resting

Short Rest

• Duration: 1 hour of light activity
• Recover: Mana equal to 1/4 of your max (rounded up)
• Use: Class abilities that refresh on short rest

Long Rest

• Duration: 8 hours (at least 6 sleeping)
• Recover: All HP, all mana, all abilities
• Limit: Once per 24 hours

Mastery

Masters of a domain treat natural 1s as regular failures instead of critical failures.

Domains:

• Melee Weapons
• Ranged Weapons
• Arcane Magic
• Divine Magic
• Athletics
• Subterfuge
• Lore
• Social
• Survival
• Crafting (specific type)

Mastery is gained through archetype progression (automatically at level 5) or specific talents.