Once you have fleshed out the motivation of you BBEG(s), the next part of your story is understanding what is scarce and what the scarcity objective or goal is. Typically, all the stories have three types of scarcity:

1. Object/Person – The most common scarcity objective is to discover, acquire, collect, and deliver an object or person. (or on the negative side to discover, acquire, withhold, and destroy.) There is usually one object/person or a multitude of objects/persons that need to be collected. This scarcity objective is the most common tactic in Fantasy adventures. This is also commonly seen in stories that utilize a prophesy or legend to foretell of an event or hero.
2. Time – The next most common scarcity objective is time. The time is fixed and is limited. Sometimes this scarcity objective can be the sole objective, like Logans Run, or it can be connected with an Object/Person objective – only having a specified amount of time to find an object, person, or arrive at a location. This objective provides a multitude of consequences as the time wanes.
3. Heroes/Hope – Sometimes the scarcity is neither an object or time, but rather heroes or hope. This is the case in Curse of Strahd. Life has become a miserable existence and what is scarce is heroes or hope. The world is miserable and will continue to be miserable unless heroes can be found to triumph over evil. No object is central to the goal, time is not limited, but despair and suffering are overwhelming.

Think first about the motivations of the BBEG and then about what is scarce and what the scarcity objectives and goals are. The scarcity objectives and goals can have multiple levels and aren’t mutually exclusive. In fact, the interplay of scarcity objectives are the most interesting when they conflict between players, NPCs, and BBEG. They don’t have to be defined only for the BBEG.