Building the Foundation: The Three-Tier Scaling System

There’s a fundamental tension in RPG design: you want players to feel more powerful as they level up, but you also want combat to stay engaging. Give them linear stat growth and high-level content becomes tedious. Give them exponential growth and they trivialize everything. Traditional MMOs solve this by making leveling progressively slower - at level 50, you’re grinding for hours just to see that XP bar creep forward.

We decided to solve it differently.

The Three-Tier Scaling System isn’t just about enemy difficulty tiers. It’s a complete rethinking of how progression, combat, and spawning systems work together. At its heart is a deceptively simple idea: what if leveling got faster instead of slower?

This post chronicles our journey from concept to implementation, the mathematical foundations that make it work, and the integrated systems that bring it all together.

The Problem We’re Solving

When we started designing Chatsubo’s combat progression, we identified several problems with traditional RPG scaling:

Problem 1: The Grind Wall

Traditional power law scaling (exponential growth) creates a “grind wall” at high levels. You’re killing the same enemies over and over, watching tiny percentages tick up on your XP bar. It feels like punishment for reaching endgame.

Problem 2: Inconsistent Challenge

Without centralized scaling, different systems implement their own math. Enemy HP grows at one rate, player damage at another, XP requirements at yet another. The result? Progression feels broken at certain level ranges - too easy here, impossibly hard there.

Problem 3: Meaningless Numbers

Some games avoid big numbers to keep combat “grounded.” Others embrace billion-damage crits. But both miss the opportunity to make numbers mean something. We wanted epic endgame numbers that still represented the same proportional challenge.

Problem 4: Static Spawning

Traditional spawn systems put enemies in fixed locations. You clear a room, it respawns. But with roaming NPCs, this creates population explosions. A room spawns 5 enemies, they roam to other rooms, the room thinks it’s empty and spawns 5 more. Repeat until the server melts.

The Solution: Centralized Power Law Scaling

Everything begins with utils/scaling.py - a single file that defines how all progression works in Chatsubo. Every combat stat, every XP calculation, every level requirement flows through this module.

The Math That Makes It Work

We use two different power law exponents for two different purposes:

Combat Scaling: level^1.5

def combat_scale(base_value, level):
    """Scale HP, damage, and XP rewards."""
    scaling_factor = level ** 1.5
    return int(base_value * scaling_factor)

This creates dramatic power growth. A level 50 player deals 353x the damage of a level 1 player. Enemy HP scales identically, maintaining consistent “attacks to kill” ratios.

Progression Scaling: level^1.3

def progression_scale(base_value, level):
    """Scale XP requirements to level up."""
    scaling_factor = level ** 1.3
    return int(base_value * scaling_factor)

This grows slower than combat power. XP requirements only scale 185x from level 1 to 50.

The Magic: Accelerating Progression

Here’s where it gets interesting. Because combat power grows faster than XP requirements, high-level players level 1.9x faster than low-level players relative to their power.

At level 1, you deal 5.5 damage and need 1,000 XP to level up. At level 50, you deal 710 damage and need 185,000 XP to level up.

That sounds like more XP is required. But the enemies you’re fighting at level 50 give 353x more XP than level 1 enemies. You’re killing them in the same number of hits but getting massively more XP per kill.

Result: Leveling feels progressively faster, not slower.

No daily XP caps needed. No artificial gates. The math just works.

Three Tiers of Challenge

Every enemy in Chatsubo belongs to one of three tiers, each calibrated for a specific number of attacks to kill:

Tier 1: Tutorial Enemies

  • Street trash, burnt junkies, weak gangers
  • 18 base HP at level 1
  • 30 base XP reward
  • Quick encounters, low threat

Tier 2: Standard Enemies

  • Gangers, thugs, enforcers
  • 35 base HP at level 1
  • 100 base XP reward
  • Main combat experience

Tier 3: Boss Enemies

  • Cyber-psychos, security bots, gang leaders
  • 68 base HP at level 1
  • 300 base XP reward
  • Epic encounters, high reward

These ratios stay consistent across all 50 levels because everything scales with level^1.5. A level 25 Tier 3 boss still takes 10-14 attacks, even though it has 8,500 HP and you’re dealing 253 damage per hit.

Level Difference Scaling: Anti-Farming and Anti-Power-Leveling

We implemented a hard cutoff system that prevents both farming trivial content and power-leveling friends:

def apply_level_difference_scaling(base_xp, enemy_level, player_level):
    level_diff = enemy_level - player_level

    # Hard cutoff: must be within +/- 5 levels
    if abs(level_diff) > 5:
        return 0

    # Within range: 10% change per level difference
    scaling_factor = 1.0 + (level_diff * 0.1)
    return int(base_xp * scaling_factor)

Enemies must be within +/- 5 levels. Outside this range = 0 XP.

Real examples:

  • Level 10 player vs Level 10 enemy: Full XP (appropriate challenge)
  • Level 10 player vs Level 15 enemy: 150% XP (risky but rewarding!)
  • Level 10 player vs Level 16+ enemy: 0 XP (too dangerous, exploit prevention)
  • Level 10 player vs Level 4- enemy: 0 XP (trivial, no reward)
  • Level 50 player vs Level 1 enemy: 0 XP (no power-leveling friends)

This prevents high-level players from dragging low-level friends through endgame content for easy XP, while still allowing some flexibility for groups with mixed levels.

Area-Based Dynamic Spawning

The Three-Tier System needed intelligent spawning that works with roaming NPCs. We built an area-based spawn manager that solves the population explosion problem.

How It Works

Instead of each room spawning independently, one spawn manager controls an entire area:

# Area configuration example
area: battle_ground
max_population: 8
spawn_rooms:
  - /rooms/battle_ground/alley_01
  - /rooms/battle_ground/alley_02
  - /rooms/battle_ground/container_maze_01
restricted_rooms:
  - /rooms/battle_ground/boss_chamber
threat_distribution:
  tier_1: 0.50  # 50% Tier 1 spawns
  tier_2: 0.35  # 35% Tier 2 spawns
  tier_3: 0.15  # 15% Tier 3 spawns

The system:

  1. Tracks total population across ALL rooms in the area
  2. Only counts living NPCs (health > 0)
  3. Spawns at random spawn points when below max_population
  4. Prevents roaming NPCs from entering restricted rooms (boss chambers stay clear)
  5. Supports per-room spawn bias to override area defaults

NPCs can roam freely within the area, and the system maintains balanced population without explosions.

Fixed NPC vs Roaming NPCs

We implemented two distinct NPC types:

Roaming NPCs:

  • Spawn at random spawn points
  • Can move between rooms in the area
  • Count toward area max_population
  • Respawn when the population dips

Fixed NPCs (Bosses):

  • Spawn at specific locations
  • Optional unique: true flag (only one exists game-wide)
  • Optional can_roam: false flag (stays in spawn room)
  • Independent respawn system
  • Don’t count toward population limits

This lets us have 8 roaming gangers in Battle Ground plus a unique boss that respawns 30 minutes after defeat.

YAML Integration: Content-Driven Configuration

All enemy templates and spawn configurations are defined in YAML files, completely separate from code:

# enemies/tier2/street_ganger.yaml
id: enemy.tier2.street_ganger
name: "Street Ganger"
tier: 2
name_variants:
  - "Street Ganger"
  - "Fresh Ganger"
  - "Rogue Ganger"
description: |
  A rough-looking street fighter with a cybernetic arm
  and a bad attitude. Clearly looking for trouble.
combat_messages:
  on_spawn: "{name} notices you and growls menacingly!"
  on_attack:
    - "{name} throws a wild punch!"
    - "{name} attempts a roundhouse kick!"
ai_config:
  aggressive: true
  flee_threshold: 0.3

The spawn system loads these templates and creates NPCs with properly scaled stats based on tier and area level. Writers can create new enemies without touching code.

Integration with Future Systems

Everything we’ve built is designed to integrate seamlessly with planned systems:

Leveling System Integration

The comprehensive Leveling System will:

  • Replace automatic stat increases with attribute point allocation
  • Add 24 skills across 4 categories
  • Implement 5 character roles with specializations
  • Use the same utils/scaling.py for all calculations

Our implementation uses the same XP tracking and level-up hooks, making migration straightforward.

Skill System Integration (Designed, Not Built)

We’ve already solved the “skill damage bonus problem” in our design:

Skills will add flat damage bonuses (not percentages). To prevent trivializing content, enemy HP includes 50% skill compensation:

def get_enemy_hp(tier, level):
    base_hp = {1: 18, 2: 35, 3: 68}[tier]

    # Assume players have 50% of expected skill for their level
    expected_skill = get_expected_skill_for_level(level)
    skill_compensation = 1.0 + (expected_skill * 0.05)

    adjusted_base = int(base_hp * skill_compensation)
    return combat_scale(adjusted_base, level)

This ensures:

  • Unskilled players find combat challenging but fair (15% more attacks than ideal)
  • Average players hit the target “attacks to kill” ratios
  • High-skill players feel rewarded with faster clears (15% fewer attacks)

Quest System Integration

The quest system is ready for enemy kill objectives:

objectives:
  - type: kill_enemies
    tier: 2
    count: 5
    description: "Defeat 5 Tier 2 enemies"

We just need to add the hook in combat_handler.py to notify the quest system when enemies die.

What We’ve Accomplished

The complete implementation of Phases 1-7 is now live in production:

Phase 1: Centralized Scaling - COMPLETE

  • Created utils/scaling.py with level^1.5 combat scaling
  • Implemented level^1.3 progression scaling
  • All systems use centralized formulas
  • Level difference scaling with hard +/- 5 level cutoff

Phase 2: Dynamic Area-Based Spawning - COMPLETE

  • Area spawn managers prevent population explosions
  • Roaming NPCs work correctly with spawn limits
  • Fixed NPCs for bosses and unique encounters
  • YAML-driven configuration for all spawns
  • Per-room spawn bias overrides for fine-tuned control

Phase 3: YAML Enemy Templates - COMPLETE

  • Enemy definitions moved to YAML files
  • Writers create enemies without touching code
  • Name variants provide variety
  • Rich combat messages and descriptions
  • Hot-reload support for content updates

Phase 4: Player Progression - COMPLETE

  • XP awarded from combat using proper scaling
  • Level-up system with stat increases
  • Character sheet with progress visualization
  • XP overflow and multiple level-ups handled correctly
  • Death penalties and respawn system

Phase 5: Health Regeneration - COMPLETE

  • Passive regeneration out of combat
  • 10-second combat delay before regen starts
  • Coordinated with combat pacing (no heal-spam needed)
  • Configurable regen rates by level

Phase 6: Combat Feedback Enhancement - COMPLETE

  • Improved combat messages with damage numbers
  • Color-coded status effects
  • Hit/miss feedback improvements
  • Death messages and combat summaries

Phase 7: Loot System - COMPLETE

  • Tier-based drop rates
  • YAML-defined loot tables
  • Currency (eddies) rewards
  • Consumable items (stim packs)
  • Equipment drops (weapons, cyberware)
  • Crafting materials and rare blueprints

The Numbers Tell the Story

Here’s what the final progression will look like once the comprehensive Leveling System is implemented:

Level 1 Player:

  • 100 max HP
  • 5.5 average damage
  • Needs 1,000 XP to reach level 2
  • Tier 1 enemy: 18 HP, ~3-4 hits to kill, 30 XP (~30-35 kills to level)
  • Tier 2 enemy: 35 HP, ~6-7 hits to kill, 100 XP (~10 kills to level)
  • Tier 3 enemy: 68 HP, ~12-14 hits to kill, 300 XP (~3-4 kills to level)

Level 10 Player:

  • HP scales with BODY attribute
  • 66.7 average damage
  • Needs 19,950 XP to reach level 11
  • Tier 1 enemy: 569 HP, ~3-4 hits to kill, 949 XP (~20-25 kills to level)
  • Tier 2 enemy: 1,106 HP, ~6-7 hits to kill, 3,162 XP (~6-7 kills to level)
  • Tier 3 enemy: 2,150 HP, ~12-14 hits to kill, 9,487 XP (~2-3 kills to level)

Level 25 Player:

  • HP scales with BODY attribute
  • 253.5 average damage
  • Needs 65,720 XP to reach level 26
  • Tier 1 enemy: 2,250 HP, ~3-4 hits to kill, 3,750 XP (~17-18 kills to level)
  • Tier 2 enemy: 4,375 HP, ~6-7 hits to kill, 12,500 XP (~5-6 kills to level)
  • Tier 3 enemy: 8,500 HP, ~12-14 hits to kill, 37,500 XP (~2 kills to level)

Level 50 Player:

  • HP scales with BODY attribute
  • 710.5 average damage
  • MAX LEVEL REACHED
  • Tier 1 enemy: 6,364 HP, ~3-4 hits to kill, 10,607 XP
  • Tier 2 enemy: 12,374 HP, ~6-7 hits to kill, 35,355 XP
  • Tier 3 enemy: 24,042 HP, ~12-14 hits to kill, 106,066 XP

The Magic of Power Law Scaling: Notice that the “hits to kill” stays constant across all levels (Tier 1: 3-4, Tier 2: 6-7, Tier 3: 12-14). A level 1 player and a level 50 player both experience the same combat pacing, just with vastly bigger numbers. This is power law scaling in action.

The key insight: Because combat power (level^1.5) grows faster than XP requirements (level^1.3), the kills-per-level actually decreases as you progress. At level 1, you need ~10 Tier 2 kills to level up. At level 25, you need ~5-6 Tier 2 kills. This creates a satisfying sense of accelerating progression - you’re getting more powerful and leveling faster.

Note: The Phase 4 minimal leveling system (currently implemented) uses simplified linear HP scaling (+10 per level) and is balanced for early levels (1-10). The numbers above represent the final comprehensive Leveling System that will use BODY attribute scaling with level^1.5.

Lessons Learned

Building the Three-Tier System taught us several crucial lessons:

1. Centralization Is Critical

Having utils/scaling.py as the single source of truth for all scaling math was the best decision we made. When we need to adjust balance, we change one exponent and the entire game adjusts proportionally.

2. Power Law > Linear

Linear scaling feels flat. Exponential scaling creates grind walls. Power law (level^1.5) creates satisfying growth that stays balanced.

3. Different Exponents for Different Purposes

Using level^1.5 for combat and level^1.3 for progression creates accelerating advancement without breaking balance.

4. Area-Based Spawning Is Essential

Per-room spawning doesn’t work with roaming NPCs. Area-based management solves population control elegantly.

5. Build Integration Points First

We documented how skills, quests, and equipment will integrate before those systems exist. When we build them, they’ll slot right in.

The Complete System in Action

All seven phases are now live and working together seamlessly:

The Player Experience (Level 1-10)

Early Game

  • Face Tier 1 tutorial enemies in Back Alley Training Ground
  • Learn combat mechanics with forgiving encounters
  • Collect basic loot (stim packs, scrap metal)
  • Passive regen means no heal-spam between fights
  • Level up quickly, seeing visible power growth

Mid Game

  • Graduate to Tier 2 standard enemies
  • Area-based spawning creates dynamic encounters
  • Roaming NPCs make each visit unique
  • Better loot drops (weapons, cyberware chips)
  • Combat becomes tactical with resource management

Advanced

  • Challenge Tier 3 bosses in designated rooms
  • Epic fights with 10-14 attack encounters
  • Rare loot and equipment upgrades
  • Multiple systems working together (regen, loot, progression)
  • Clear sense of power progression

The Technical Achievement

What makes this system special isn’t just the individual phases - it’s how they integrate:

Centralized Scaling ensures every number in the game comes from the same mathematical foundation. Change one exponent and combat, progression, loot, and regen all adjust proportionally.

Dynamic Spawning creates a living world where enemy populations feel natural. Fixed bosses guard key locations while roaming enemies create unpredictable encounters.

YAML Content System empowers writers to create rich, varied enemies without touching code. Hot-reload means content updates go live in seconds.

Player Progression uses accelerating XP curves that make high-level play faster, not slower. No grind walls, just satisfying advancement.

Health Regeneration eliminates tedious healing between fights while preserving tactical resource management during extended encounters.

Combat Feedback provides clear, immediate information about damage, effects, and outcomes without overwhelming the player.

Loot System creates meaningful rewards for combat using tier-based drop tables that scale with enemy difficulty.

The Numbers Prove It Works

Real gameplay data from the Battle Ground:

Tier 1 Enemy (Level 1)

  • 18 HP, dies in 3-4 hits
  • Awards 30 XP
  • 60% chance to drop loot
  • Common drops: Stim Pack Basic, Scrap Metal
  • Combat duration: 6-10 seconds

Tier 2 Enemy (Level 2)

  • 99 HP, dies in 6-7 hits
  • Awards 283 XP
  • 40% chance to drop loot
  • Uncommon drops: Weapons, Cyberware Chips
  • Combat duration: 15-20 seconds

Tier 3 Boss (Level 2)

  • 193 HP, dies in 12-14 hits
  • Awards 566 XP
  • 80% chance to drop loot
  • Rare drops: Military Weapons, Advanced Cyberware
  • Combat duration: 30-40 seconds

The math holds true: consistent “attacks to kill” ratios across all levels, with XP rewards that create accelerating progression.

What’s Next: Beyond the Three-Tier Foundation

With all seven phases complete, the Three-Tier System provides a rock-solid foundation for future development:

Comprehensive Leveling System (Future)

  • 6 primary attributes (BODY, REFLEX, TECH, INT, COOL, EMP)
  • 24 skills across 4 categories
  • 5 character roles with specializations
  • Builds directly on Phase 4’s XP/level framework
  • Uses the same scaling formulas we’ve proven

Advanced Combat Systems (Future)

  • Status effects and debuffs
  • Cover and tactical positioning
  • Team combat and formations
  • Special abilities and ultimates
  • All balanced using existing scaling math

Economy and Crafting (Future)

  • Loot system already provides materials
  • Tier-based component system
  • Equipment upgrades and modifications
  • Vendor pricing uses scaling formulas

Quest System Integration (Future)

  • Kill objectives already track tier/count
  • XP rewards use progression scaling
  • Equipment rewards from loot tables
  • Difficulty scaling per player level

The Foundation Is Strong

The Three-Tier Scaling System isn’t just about combat balance - it’s a complete framework for progression that makes numbers meaningful, leveling rewarding, and endgame exciting.

With all seven phases complete, we’ve delivered a system where:

  • A level 1 player can understand the tiers and make tactical decisions
  • A level 25 player feels dramatically more powerful while facing proportional challenges
  • A level 50 player sees epic numbers that still represent balanced gameplay
  • The entire journey from 1-50 takes 20-25 hours of gameplay, with leveling accelerating instead of grinding to a halt
  • Combat feels rewarding with loot drops, regeneration, and clear progression
  • Writers can create content without touching code
  • The world feels alive with dynamic spawning and roaming NPCs

And perhaps most importantly, we’ve built it in a way that integrates cleanly with every future system. The comprehensive Leveling System will slot right into the XP framework we’ve proven. Advanced combat features will use the damage formulas we’ve validated. The economy will build on the loot tables we’ve established.

The foundation is strong, the implementation is complete, and the system is production-ready.

Want to experience it yourself? Join us in Chatsubo MUD and fight your way through the Battle Ground. Experience power law scaling, dynamic spawning, tier-based loot, and all seven phases working together in a living, breathing cyberpunk world.