The Game
The Game (p.7) 
| The PHB’s description of AD&D as a game of collaborative imagination, with a Game Master (GM) who referees the world and players who direct their characters through it, applies in Oath-Bound as written. The relationship between GM and players, and the basic premise of play, are unchanged. |
The Oath-Bound setting has a specific register worth knowing before play begins. It is neither grimdark nor high fantasy. The world does not wallow in suffering, but it does not protect characters from consequence either. Magic is real but not ubiquitous. The gods are present and have opinions. The social and legal structure of the setting runs on sworn obligation — what you promise matters, and the consequences of breaking a promise are not merely social.
Players who arrive expecting a setting that resembles heroic fantasy of the standard type will find much that is familiar and some things that are not. The differences emerge through play rather than through prior study. Arriving at Session Zero with an open mind about what kind of character you want to play is more useful preparation than reading ahead — and the next section explains exactly why Session Zero matters and what to expect from it.