When playing the Star Wars RPG there is a special system used for the players that varies based on core game. Morality, Obligation, and Duty. These are from Force and Destiny, Edge of the Empire, and Age of Rebellion respectively. These systems vary greatly from one another and so fi you are using multiple core books it can be a challenge to determine which you should use. I’ll break down the three systems and then give my opinion on which to use.
Morality is the system meant for Force users and is integral to the conflict system. This uses the characters actions throughout the session to determine how their morality is. At above 30 you are a light side user but below that and you fall to the dark side. A new player begins at 50. This is important to Force users as it can change what points you gain from Force rolls and Destiny Point allocation. However, for non-Force users this mechanic doesn’t serve much purpose besides potentially taking away Destiny Points.
Obligation is the core focus of Edge of the Empire and is basically anything that can prevent or interrupt a characters attempt to do what they want. Whether it be debt to a Hutt or a bounty on their head or even a sick family member that prevents them from traveling off world, these obligations interfere with a characters freedom. This can often be one of the driving forces behind a party’s actions. Obligation can be gained or lost through actions of the party and can often come into play to throw a hitch into whatever they’re doing at the moment. This is the most flexible system as it can apply to anyone from any background or game.
Duty represents your successes and reputation within an organization, particularly the Rebellion. This can be repurposed for almost any other organization though and so is a bit flexible. As the party achieves victories they are rewarded duty for those accomplishments such as intel gathering or combat victory. When they reach a certain level their duty is reset to 0 and they gain a command rank or other viable rank. This allows them to requisition better gear for free and increases their renown and respect within the organization.
Out of the three if you needed to pick one for a multi group party I would say obligation is the best due to how universal it is. My personal preference, however, is a combination of morality and obligation. I often run groups with mixed characters and I will give them morality and obligation as I find the moral strength and weakness dynamic interesting for roleplay purposes and a jedi in a group of morally bankrupt bounty hunters can generate more conflict for them as they deal with so much dark side influence. Duty is the one I use the least due to it being for an organization, and best fit for military organizations. However, if running a Rebellion or Imperial campaign it works rather well, even if the characters aren’t a dedicated part of those groups. A group of Bounty Hunters helping the Empire can start earning duty and use the ranks to demand more credits, credits in advance, or more respect within the Empire. Smugglers can earn the same with the Rebellion to cause the Rebellion to turn a blind eye to their activities with Hutts. The best answer is the generic one of whatever fits your story but if I needed to give an answer I would say a combination of obligation and morality make the best roleplay experience with duty being good when applicable.