I think there is still a mental disease aspect. Sociopathic or extremely narcissistic people can also seem evil, but at the end of the day they are still mental diseases. I would even go as far as to say that anyone who wants to be a billionaire is probably a mixture of sociopathy, narcissism and has some sort of addiction (ps: not an expert basing this only on common sense).

I could perhaps say wanting to own billions is a symptom of multiple mental diseases.