Gaming Rules-design note One Hero Engine

One Hero Engine: Quick Reference

A consolidated quick-reference page for the current One Hero Engine draft.

Character creation

  1. Assign Stats: 14, 13, 12, 11, 11, 11. You may redistribute up to 2 points between any scores.
  2. Choose a Race.
  3. Choose a Class.
  4. Pick 3 Tags.
  5. Choose a Casting Path (optional).
  6. Finalize confirmed derived stats: modifiers, save specializations, AC, to-hit bonus, damage bonus, Soak, and MP if applicable.

Rules review required: Starting HP, HP gained by level, initiative baseline, default weapon damage steps, starting equipment, and spell counts are not defined consistently in the current source.

Attribute roles

StatRole
STRStrength - Melee, grapples
DEXDexterity - Reflexes, stealth
CONConstitution - Endurance, poison
INTIntelligence - Lore, logic
WISWisdom - Willpower, awareness
CHACharisma - Presence, persuasion

Modifier guide

Modifier Formula: (Stat - 10) / 2, rounded down

ScoreModifier
1-5
2-3-4
4-5-3
6-7-2
8-9-1
10-110
12-13+1
14-15+2
16-17+3
18-19+4
20-21+5

Checks and saves

  • Skill check: Roll 1d20 equal to or lower than the relevant stat.
  • Non-spell save: Roll 1d20 + modifier against a TN set by the GM, scenario, or encounter.
  • Spell save: Roll 1d20 + modifier against the caster’s Spell Save TN.
  • Spell Save TN: Equal to the caster’s full stat score.
  • Advantage (roll-over): Roll 2d20 and take the higher.
  • Disadvantage (roll-over): Roll 2d20 and take the lower.
  • Advantage (roll-under): Roll 2d20 and take the lower.
  • Disadvantage (roll-under): Roll 2d20 and take the higher.

Difficulty numbers

DifficultyTN
Easy6
Average11
Hard16
Legendary20

Combat basics

  • Turn sequence: Start of turn -> 2 actions -> 1 Trait if desired -> resolve rolls -> narrate -> enemy turn or Oracle twist
  • AC: 9 + Dex modifier
  • To-Hit: Higher of STR or DEX modifier
  • Damage: STR for melee; DEX for ranged
  • Soak: (AC - 10) / 2, rounded down
  • Nat 20: Bypasses Soak
  • Nat 1: Attacker takes damage instead

Rules review required: The current source does not define a full initiative rule, default enemy defence values, default weapon damage steps, or a complete combat-ending procedure consistently.

Damage steps

StepDie
11d4
21d6
31d8
41d10
51d12
61d20
7+1d20 + 1dX

Damage conversion

Total RollConverted Damage
0-10
2-51
6-92
10-144
15-185
19-226
+4+1 more

Fray

  • Levels 1-5: 1d6
  • Levels 6-10: 1d8
  • Overflow may hit another enemy with equal or lower AC

Rules review required: The current source does not define lower-HD foes, boss interaction, or full Fray eligibility consistently.

Morale

Rules review required: The current source material does not define this procedure consistently.

Oracle

  • Roll 2d6: Chance and Risk
  • Chance > Risk = Yes
  • Risk > Chance = No
  • Both dice 1-3 = Yes/No, but…
  • Both dice 4-6 = Yes/No, and…
  • Equal values = Yes, but… and gain 1 Twist Point

Twist Points

  • Gain 1 when dice are equal, a Trait or Spell grants it, or a major failure is narratively impactful
  • At 3 Twist Points, introduce a dramatic twist

Magic

  • MP: 5 + casting stat modifier
  • MP recovery: 1d4 after an 8-hour long rest
  • HP to MP: Sacrifice 2 HP to recover 1 MP
  • Mythic Spells: 3+ MP, once per session, always succeed

Rules review required: The current source does not define a universal casting roll, failed-casting rule, concentration subsystem, or global summoning procedure consistently.

Advancement

LevelGains
11 Race Trait, 1 Class Trait, 3 Tags
2Gain 1 Trait
3+1 to a stat
4Gain or upgrade a Trait
5+1 to a stat
6Gain Trait (any source)
7+1 to a stat
8Gain Trait
9+1 to a stat
10Capstone or transformation

End of article

Part of: One Hero Engine

View the complete series

Continue reading

Series

One Hero Engine

Tags

Solo Rpg One hero engine Homebrew rules