Demons always make you believe that you are in control of them, and that they are there just to give you powers. In the end, the demon always gains total control over any mortals that lose their wisdom over greed.
I'm sure it's just another mortal about to be mane fodder.
The bananas were funny though. But it's funny because the designers of Civ decided that bananas were a resource significant enough to be included, rather than staples like salt, tea and olives, actual strategic health resources.