The Kings are the guards of the borders. They determine what gets in and what gets out. When a King appears I check if something needs to be guarded ( for example in case of the Coins material matters; could be health, the place that one lives in; the body; money matters...).
A King may indicate that we need to protect something; or that is is sensible to protect ourself.
Sometimes it can also mean that one must open up; then the King has become too controlling; a tyrant who lets nothing out nor in.