“Billions,” a Showtime series set in the world of high finance, is about the flow of power and money. It is driven by the egos of, for the most part, male characters who spit lines such as “What’s the point of having f— you money if you never say f— you?”

The chemistry of this testosterone-laden setup was altered with the introduction of a reserved, androgynous character named Taylor Mason. In the second season, this computational savant came in as an intern to the fictional hedge fund Axe Capital, quickly becoming the secret...