Who's Who in the DC Universe (usually referred to as Who's Who) is a guide that DC Comics published to catalogue the wide variety of fictional characters in their imaginary universe, the DC Universe. DC Comics is one of the largest companies in comic book and related media publishing. ... A fictional character is any person who appears in a work of fiction. ... A fictional universe is a cohesive fictional world that serves as the setting or backdrop for one or (more commonly) multiple works of fiction. ... The DC Universe (DCU) is the fictional shared setting where most of the comic stories published by DC Comics take place. ...