This technical note proposes a role-separated Game Master architecture for AI-assisted PBM (Play by Mail / Play by Message) and online TRPG systems. The work is part of the “Multi-user Play-by-Online Architecture Concept” series, and focuses specifically on the Game Master layer. It defines the Game Master not as a single adjudicating persona, but as a set of separated operational roles: Main GM, SubMaster, External Dice / Independent Judgment Layer, Operator, and Player. In this architecture, the Main GM publicly declares the roll context, stakes, modifiers, and judgment conditions. The External Dice / Independent Judgment Layer determines the numerical result independently of AI or operator intent. The SubMaster translates the fixed result into rule-compliant narrative output without modifying the outcome band. The Operator manages system configuration, auditing, account control, and operational policy, but does not alter in-session dice results or outcome bands. The purpose of this structure is to preserve player agency, randomness, auditability, reproducibility, and fairness while allowing AI to support natural language interpretation, translation, narrative output, and operational assistance. AI is positioned not as a judge or ruler, but as a support layer that connects player actions, rules, operators, and fictional worlds. This document includes:- Role architecture for Main GM, SubMaster, External Dice / Independent Judgment Layer, Operator, and Player- Permission Matrix- Main GM / Sub GM relationship diagram- Runtime Sequence Diagram- Human GM Operational Flow- Discussion of PBM and online TRPG compatibility- AI Usage Disclosure- Copyright and license statement- Reference Hash AI Usage Disclosure:Interactive AI systems, including large language models, were used as editorial assistance for structural organization, wording refinement, diagram preparation support, and TeX/PDF composition support. AI was used only as a support tool for organization and expression. The design philosophy, conceptual structure, architectural decisions, terminology selection, and final content decisions were made by the author. License:© 2026 kurato. Licensed under CC BY-NC 4.0. This work may be cited, shared, and adapted for non-commercial purposes, provided that appropriate credit is given to the original author. Commercial use is prohibited. This record is an alternate language version of the corresponding Japanese/English version. Japanese version:https://doi.org/10.5281/zenodo.20068432
kurato (Thu,) studied this question.