Solo Heroes: Solo Adventure Rules for Labyrinth Lord

Overview

Solo Heroes is a rules supplement by Kevin Crawford for running Labyrinth Lord adventures (and compatible OSR games) with a single player character instead of a full party. It provides mechanical adjustments that preserve the adventure experience while making solo play viable.

The Solo Play Problem

Standard OSR adventures assume party play, creating several challenges for solo heroes:

Lack of skill diversity: Single characters rarely possess all abilities a party has (healing, locks, arcane knowledge, combat strength)
Hit point depletion: Enemies calibrated for party damage output can eliminate a solo character in a few rounds
Instant death effects: Single failed saves against death magic, poison, or environmental hazards become campaign-ending
Combat time: Solo characters need many more hits to eliminate enemies designed to be defeated by multiple attackers

The Five Core Rules

Rule 1: Damage Dice Reinterpretation

All damage dice use a compressed scale: - Roll of 1 = 0 damage - Roll of 2-5 = 1 point of damage - Roll of 6-9 = 2 points of damage - Roll of 10+ = 4 points of damage

Modifiers (Strength, magic) apply to one die of choice. Flat damage converts at 1 point per 4 full points stated.

Effect: Reduces damage variation while keeping it random, making combat last longer for both sides.

Rule 2: The Fray Die

Solo heroes gain a bonus die roll each round representing incidental combat effectiveness:

Fighters: 1d8
Clerics/Thieves/Others: 1d6
Magic-Users: 1d4

The Fray die does automatic damage (no hit roll needed) against foes with equal or fewer hit dice than the hero (magic-users can harm any foe). Excess damage spills to adjacent enemies of equal or worse armor class. Damage from the Fray die counts as full hit dice against enemies.

Effect: Heroes deal guaranteed damage every round, preventing frustrating rounds where they miss entirely.

Rule 3: Healing

Curative potions: Healed hit points equal the reversed damage die roll
Natural healing: Five minutes of rest after combat heals up to 2 points of damage (cannot exceed pre-combat total)

Effect: Healing is faster and more abundant, compensating for the solo hero's increased damage exposure.

Rule 4: Defying Death

When facing instant-death effects, failed saves against death spells, inescapable traps, or insurmountable barriers, heroes can attempt to Defy Death:

First attempt: Roll 1d4 per character level, take that much damage
Second attempt: Roll 1d6 per level
Third attempt: Roll 1d8 per level
Fourth+ attempt: Roll 1d10 per level

If damage would reduce hero to 0 HP, they're left at 1 HP and the doom takes normal effect.

Effect: Prevents arbitrary character death while keeping danger escalating.

Rule 5: Experience and Henchmen

XP: Solo heroes earn only 1/4 normal experience points (fewer hands to divide treasure)
Henchmen: Can be employed but are treated as monsters for damage purposes (1 HD henchman dies from 1 point of damage)

Effect: Slows solo advancement and discourages relying on hires for combat.

Mechanical Results

Against equal or weaker foes: A solo hero with even modest hit points can overcome multiple lesser enemies per round through combination of regular attacks and Fray die damage.

Against superior foes: Combat becomes dangerous but winnable. A first-level fighter with 5 HP and chain mail fighting a 4 HD ogre might need multiple lucky hits but stands a reasonable chance.

Party vs Solo comparison: A party is designed to absorb many hits and divide enemy attention. These rules let a solo character mitigate both issues without breaking game balance.

Optional Rule Layer From Source

The source includes a second procedural layer for campaigns that want stronger protagonist continuity and smoother one-player operation.

Enduring Protagonists

PCs use maximum HP by class and level.
At 0 HP, the protagonist is removed from the scene but does not die automatically.
The cost is campaign friction: mission failure from lost time, capture, lost gear, or a constrained second-chance attempt.

Use this when campaign continuity matters more than strict lethality.

Automatic Initiative

Solo hero wins open-combat initiative by default.
Ambush and surprise still apply.

This creates a reliable escape window in encounters that would otherwise become unavoidable action-economy losses.

Extra Fray Dice as Situation Reward

The referee can add temporary Fray dice for major positional or tactical advantages:

+1 die: useful edge.
+2 dice: strong advantage.
+3 or more: decisive setup.

The source recommends awarding only the strongest single circumstance rather than stacking many minor edges.

One Pair of Hands Rule

If adventure logic requires multiple simultaneous actors, simplify the obstacle for one adventurer:

collapse split-key or split-task constraints,
allow lone-hero equivalents,
preserve pressure elsewhere.

This keeps module structure usable without full rewrites.

Conversion Notes for Other OSR Chassis

Source guidance for ports:

For high-HP systems, normalize toward roughly 10 HP/level for tough classes and 4 HP/level floor for frailer classes.
Translate extra attacks into larger or additional Fray dice instead of full extra attack sequences.
Keep damage reinterpretation and Defy Death intact as core solo-balance components.

One-on-One Referee Workflow

For one referee + one player sessions, run this loop:

Present clear threat and retreat vectors.
Resolve combat with Fray and damage reinterpretation.
Apply five-minute post-fight first aid and resource check.
Escalate risk through Defy Death only for true fail-state events.
Convert next obstacle if it requires multiple simultaneous actors.

This preserves old-school challenge while avoiding brittle single-roll campaign collapse.

Philosophy

Solo Heroes treats the problem as a scaling issue: modify the numbers to make the mathematics work for one character instead of four to six. Rather than redesigning adventures, these rules fit between the written module and character sheet.