Zill O'll is a nonlinear fantasy role-playing game set on the continent of Vyashion. Following the fall of Emperor Balor, a fragile peace settles over the land as a new threat begins to emerge with the awakening of the Dragon King. Players create their own protagonist and choose from different starting scenarios before setting out on an open-ended adventure. The game's free-scenario system allows events to unfold according to the player's actions and the passage of time, affecting relationships, the fate of major characters, political conflicts and the eventual ending. Combat is turn-based, while character development revolves around the game's Soul system.