Primary Motive is about the character's ideal on why they want to strive for their goal and the reasons for their morality. It is a part of the Morality System, basically it’s core element from where the character’s moral philosophy and worldview are derived.
The most common Primary Motives are the ones listed below, though a character may have a more specific one.
Unconditional (Heroes striving primarily into good stability for society. For obvious reasons, a villain can’t have this motive - Barney the Dinosaur)
Dread (Trauma experienced heroes that are primarily dreaded - Batman)
Victory (Ego Driven characters, primarily in it to just win it. - L Lawliet, Sheldon Cooper)
Casual (Characters who are not so much in between either of the criteria, such being uncertain, ambiguous, and unpredictable to verify. - Sly Cooper, Rhino from Spider-Man)
Ambition (characters who behave like god wannabe harbingers for rebirth, or their goals were a means to an end. Heroes only qualify if there are some heroic achievements from this. - Light Yagami and Griffith)
Revenge (Primarily into vengeance, or a self-need that the character desires.)
Depravity (Villains who seek to get what they want by any means necessary, either by stealing pleasure from others, or expressive Nihilism. Heroes can’t have this motive - Vukmir.)