Benevolent overlord noun phrase informal
A person, group, or government which has power and control but does not act tyrannically
Peter acts as a good boss, but he always talks behind our backs. Such a benevolent overlord!
Today, our benevolent overlord allows us to leave work early.
If you do something out of the goodness of your heart, you do because of your altruistic generosity or goodwill.
The phrase "benevolent overlord" is used with ironical or sarcastic meaning, therefore, people should use it in the appropriate context.
If someone has a cast iron stomach, they have a strong stomach that can digest unusual food and even bad food without being ill.
Jimmy must have a cast-iron stomach, when he drank milk with lime juice and felt perfectly fine afterward.