Special obligations arise from particular relationships, commitments, or roles rather than being owed to everyone equally. Promises, friendship, family, and professional responsibilities are common examples. They are agent-relative: the reason you have to act can depend on your own connection to the person concerned.
A special obligation can arise through a promise, a relationship of dependency, or a role with entrusted responsibilities. These grounds do different work. Promises involve undertaking a commitment, while caring for a dependent person may be required without a voluntary agreement. Role obligations also need justification: an employer’s instruction is not automatically a moral duty. Explaining the ground helps determine who is owed what and whether the obligation survives a change in circumstances.