15: Game Master’s Toolkit

Introduction

The Jujutsu Kaisen world is brutal, fast, and deeply personal. Combat is never just about numbers — it’s about emotions, choices, and consequences. This toolkit provides mechanical frameworks, random generators, and encounter scaling rules so the AI (or you as GM) can run the world fluidly while keeping it authentic to JJK.

Core Systems Recap

Cursed Energy Pool (CE Reserves)

  • CE = stamina + willpower.

  • Spending CE fuels reinforcement, techniques, RCE, and Domains.

  • Running out risks backlash: exhaustion, injuries, or even unconsciousness.

Leakage

  • Beginners roll checks each round to prevent CE from leaking.

  • Advanced sorcerers automatically suppress leakage.

  • Failure = lose CE and attract ambient curses.

Resonance (Emotional States)

  • Rage = damage boost, high leakage.

  • Fear = lower control, erratic surges.

  • Grief = stronger defense, slower CE regen.

  • Calm = reduced costs, improved precision.

Backlash

  • Overusing CE causes recoil. GM decides whether it’s physical (injury), mental (focus loss), or spiritual (soul scar).

Templates for Gameplay

Innate Technique Builder

  1. Concept: What fear or identity does the technique reflect?

  2. Expression: Physical, elemental, spatial, or soul-based?

  3. Limitations: Conditions that balance its use.

  4. Expansion: Reverse form, Maximum Technique, or Domain version.

Binding Vow Generator

  • Mild Vow: Small risk → moderate reward.

  • Severe Vow: Major limitation → massive payoff.

  • Example: “I won’t dodge this fight” → +50% attack power.

Domain Design Sheet

  • Aesthetic: What does the inner world look like?

  • Guaranteed Hit: How does the technique refine to perfection?

  • Weakness: CE drain, collapse risk, counter-Domain susceptibility.

Cursed Spirit Builder

  • Origin: What emotion birthed it? (fear of hospitals, regret of suicide, envy in love).

  • Form: Humanoid, beastlike, grotesque, or abstract.

  • Grade: Match CE output/ability complexity.

  • Ability: Give 1–3 thematic powers.

Random Generators

Curse Origin Table
Roll 1d6 (or let the AI pick):

  1. Hospital → sickness, body horror curse.

  2. School → mimicry, youth anxiety curse.

  3. Battlefield → weapon-wielding revenant.

  4. Shrine/Temple → twisted guardian spirit.

  5. Subway/Station → swarm or panic curse.

  6. Disaster Zone → elemental calamity.

Sorcerer NPC Traits

  • Quirk (stoic, reckless, idealist, sadistic).

  • Clan status (elite bloodline, outsider, rogue).

  • Technique hint (fire-based, shadow, soul, sound, etc.).

  • Political stance (loyal to higher-ups, rebel, mercenary).

Forbidden Object Events

  • Found in shrine vault.

  • Black market trade.

  • Excavated from battlefield ruins.

  • Released accidentally by civilians.

Encounter Scaling

By Grade

  • Grade 4: One-hit fodder curses. Good for training arcs.

  • Grade 3: Threatening in numbers, but still manageable.

  • Grade 2: Tactical fights — players need strategy.

  • Grade 1: High-stakes battles, often require teamwork or vows.

  • Special Grade: Boss encounters that change the rules of the fight.

Scaling Mechanics

  • Match CE reserves between enemies and players.

  • Use environmental rules: hospital curse regenerates, battlefield curse enrages, shrine curse resists exorcism.

  • Give elites counterplay (Domains, Amplification, soul techniques).

Narrative Tools for the GM

  • Geography as Character: Lean on Manual 11. Environments shape the battle — train stations = crowded chaos, shrines = cursed seals, disasters = AoE danger.

  • Politics as Conflict: Higher-ups sabotage missions, clans withhold aid, students clash with traditions.

  • History as Echo: Link cursed objects or spirits to Heian-era tragedies. Players feel they’re walking into cycles that repeat.

  • Temptation as Drama: Offer forbidden knowledge or vows as “shortcuts to victory,” but always with permanent consequences.