Who she is: Amanda Waller
Her power: No superpowers, just a meanass attitude and the bravado befitting a government agent capable of not being intimidated by metahumans.
Her story: Amanda Waller is introduced in Suicide Squad as a government operative who comes up with the plan to put together Task Force X, composed of supercriminals pushed into service to embark on highly dangerous missions in exchange for perks and reduced sentences. She activates the team when one of her first recruits, an evil mystic called the Enchantress, breaks free of Waller’s control (it’s a whole silly thing involving the magical being’s heart) and tries to eliminate humanity with the help of her equally powerful brother, Incubus. Waller is trapped inside Midway City where Enchantress has seized power, and the agent tries frantically to eliminate the paper trail of her responsibility for the fiasco. Lucky for her, Task Force X rescues her and kills Incubus and Enchantress. In a credit sequence stinger, Waller meets with Bruce Wayne, who offers to protect her from those looking to take her down for the events of the movie, in exchange for her turning over the government files on metahumans to him.
Played by: Viola Davis
Currently, Amanda Waller is: Still in the employ of the U.S. government, and probably mapping her next clever bureaucratic move.
Where will we see her next? Suicide Squad 2 is the obvious assumption, though a cameo in another DC film is possible.