The term "mysterious leader" refers to an individual who holds a position of power or influence, but whose true character, motives and intentions are not fully understood by others. Full definition
New faces, both friend and foe, will join the series, including the no - nonsense, highly - skilled and somewhat mysterious leader (Constance Zimmer) of the ATCU (Advanced Threat Containment Unit), her intimidating partner, Banks (Andrew Howard), Lash (Matthew Willig), a monstrous Inhuman whose loyalties remain ambiguous, and new Inhuman Joey (Juan Pablo Raba), who is struggling to harness his newfound abilities, among other surprising characters. (flickeringmyth.com)
In the comics, Blackhawk was the mysterious leader of the Blackhawk Squadron, an elite but small group of ace - pilots who fought in World War II. (indianexpress.com)
One thing leads to another, and soon enough Gnomeo, Juliet, Holmes and Watson are barreling through London, solving mysteries and foiling the kidnapping scheme of two dopey gargoyles and their mysterious leader. (thewrap.com)