Introduction

Oath-Bound is a grounded, early-medieval world in which the familiar structures of the game remain in place but are reinterpreted so that power does not sit cleanly with the individual; arcane practice still appears as spellcasting but is understood as the risky shaping of a real and unstable force, while clerical “spells” reflect participation in a system of oaths and institutional authority rather than a personal reserve of power, and across both domains the world retains momentum, so actions persist, consequences accumulate, and the rules are applied through that lens—producing play that looks recognizable on the surface yet operates with greater weight, continuity, and dependence on context than a typical baseline game.

This Overlay documents the major differences in the rules and setting between 'Classic' AD&D First Edition and the ones used in the World fof Oath-Bound. Where these differences are significant, commentary is available to explain why those changes have happened.