I don't want to give apoilers away regarding the overall plot, but suffice it to say that this character is immensely important. As of now, only revealed as the mysterious A, this shadowy figure is a man on a mission and should encapsulate the qualities of drive and focus. He doesn't think of himself as the best, but enough people have given him that reputation that he views the notion as a tool to use against his enemies.  His scene at the tail end of this chapter is the first glimpse into a wider world, and the voice coming through the phone should be calm, soothing, but ominous all the same. This isn't some mustache-twilring villain, this is a character first and foremost. I will audition myself if need be, though I'm not sure how I would feel about having to. For something in the vocal ballpark, think Itachi Uchiha or Troy Baker's Batman. 

-Elliott, Creator of Warriors