Table of Contents

Core System

ODDS RPG uses:

The system is genre-neutral and supports cinematic but tactical play.

Only roll when:

If nothing changes, do not roll.


The Core Roll

When attempting something risky:

Roll 1d20 + Attribute + Skill

Compare the result to a Target Number (TN).

Difficulty TN
Easy 8
Standard 12
Challenging 15
Hard 18
Extreme 22

If the result meets or exceeds the TN, the action succeeds.

If the result is lower, the action fails and the GM introduces a consequence.


Degrees of Success

If you exceed the TN by:

5 or more → Strong Success  
10 or more → Critical Success  

Natural 20:

Automatic Strong Success.

Natural 1:

Failure plus Complication.

Strong Success may grant:

Critical Success may grant:

The GM determines the exact benefit based on the situation.


Attributes

Attribute Represents
Might Strength, endurance, durability
Agility Speed, reflexes, coordination
Mind Logic, perception, technical ability
Presence Willpower, charisma, leadership

Starting array:

+2, +2, +1, +0

Attribute maximum depends on campaign Tier.


Skills

Skills represent training or specialization.

Untrained skills default to +0.

Roll:

1d20 + Attribute + Skill

The GM may approve new skills appropriate to the setting.


Impact Rolls

When a successful action causes measurable effect:

Roll 2d10 + relevant modifier

Impact is used for:

Armor reduces incoming damage.

Impact cannot be reduced below 0.


Combat Structure

Combat occurs in Rounds.

At the start of combat:

Each participant rolls 1d20 + Agility for Initiative.

Highest result acts first.

On your turn, you may take:

1 Move  
1 Action  
1 Minor Action (optional)

You may trade:

Move → Minor  
Action → Move  

You may not trade a Minor into a full Action.

Keep turns concise and decisive.


Actions

Common Actions include:

Common Minor Actions include:

The GM has final say on action categories.


Attacking

To attack:

Roll 1d20 + Attribute + Combat Skill

Compare against the target’s Defense TN.

On a hit:

Roll 2d10 + relevant Attribute for damage.

Armor reduces the damage taken.


Defense & Positioning

Base Defense TN: 12

Modifiers:

Partial Cover:

+2 Defense

Heavy Cover:

+4 Defense

Prone:

+2 vs ranged attacks  
-2 vs melee attacks  

High Ground:

+1 to attack rolls

Flanking:

+2 to attack rolls when an ally threatens the target from the opposite side

Modifiers should not stack beyond what is reasonable.


Range Bands

ODDS uses abstract distance:

Engaged – melee distance Close – same room Near – across open area Far – long range Extreme – sniper range

Attacks beyond optimal range:

  1. 2 per range band beyond intended use.

Health & Resolve

Health = 10 + Might Resolve = 10 + Presence

Health measures physical durability. Resolve measures morale and mental stability.

When Health reaches 0:

The character is Downed.

While Downed:

You may take 1 Action per round.

If you take additional damage while Downed, roll 1d20:

1–10: Unconscious  
11–19: Stable but still Downed  
20: Regain 1 Health  

If you take damage equal to your full Health again while Downed:

You are dying (GM discretion).

Resolve Damage

Some effects reduce Resolve instead of Health.

When Resolve reaches 0:

The character is Broken.

A Broken character:


Conditions

Conditions do not stack with themselves.

Shaken:

  1. 2 to next roll

Wounded:

  1. 2 to physical rolls

Frightened:

  1. 2 to mental rolls

Restrained:

Movement prevented

Stunned:

Lose next Action

Conditions last until resolved by time, action, or GM ruling.


Advantage & Disadvantage

Advantage:

Roll 2d20, take the higher result.

Disadvantage:

Roll 2d20, take the lower result.

Multiple sources do not stack beyond one level.


Assisting

To assist an ally:

Roll TN 12 using a relevant skill.

On success:

Ally gains +2 to their next roll.

On Strong Success:

Ally gains Advantage instead.

Extended Tasks

Used for hacking, rituals, repairs, negotiations, or other multi-step goals.

Set a Progress Goal (3–10).

Each success:

+1 Progress

Strong Success:

+2 Progress

Failure may:

Extended Tasks should remain dynamic.


Environmental Hazards

Fire:

TN 12 Agility or take 2d10 damage

Falling:

2d10 damage per range band fallen

Poison:

TN 12 Might or lose 2d10 Health over time

Radiation / Corruption:

TN 15 Might or lose 2d10 Resolve

Adjust TN based on severity.


ODDS RPG Core v1.0 Playtest