The victim may be plied with alcohol or drugs or deprived of sleep to help disorientate them.
Emotional blackmail is a term coined by psychotherapist Susan Forward, about controlling people in relationships and the theory that fear, obligation and guilt (FOG) are the transactional dynamics at play between the controller and the person being controlled.
Control may be helped through economic abuse thus limiting the victim's actions as they may then lack the necessary resources to resist the abuse.
In D&D, fear-immune creatures are immune to intimidate.
Understanding these dynamics are useful to anyone trying to extricate from the controlling behavior of another person, and deal with their own compulsions to do things that are uncomfortable, undesirable, burdensome, or self-sacrificing for others.
There are different levels of demands - demands that are of little consequence, demands that involve important issues or personal integrity, demands that affect major life decisions, and/or demands that are dangerous or illegal.
Completely unintelligent monsters such as some constructs, some undead, and all vermin, are immune to social manipulation.
Note that some rare monsters do not follow the normal threat mechanics.