Catwoman has been a central figure in Batman's rogues' gallery, as well as one of his most common love interests. Initially a mere cat burglar turned feline femme fatale, her origin and characterization were radically changed in the Post-Crisis on Infinite Earths DC Universe. Her new origin in Batman: Year One also introduced her sidekick named Holly Robinson.
Holly Robinson remained a somewhat minor character after Year One before coming back in Ed Brubaker's run on Catwoman. Reunited with Catwoman and eventually briefly taking her place, Holly Robinson's current path might change her forever.
Holly Robinson was created by Frank Miller and David Mazzucchelli and introduced in the landmark title Batman: Year One. She was a young prostitute who was friends with the dominatrix Selina Kyle and ended up going with her once Selina left that lifestyle. Holly is actually instrumental in Bruce Wayne taking on the mantle of Batman, as she fearlessly stabs him in the leg when he operates in an earlier, less threatening disguise. Selina would leave Holly at a convent where her sister Maggie was a nun, but when she grew up, she would marry and later be killed by a crook who Selina stole from.
This death was subsequently retconned over a decade later in Ed Brubaker's Catwoman run, with the suggestion being made that her death was completely written out of continuity via the storyline Zero Hour. It was explained that she and Maggie left the convent, with Holly later falling on hard times and returning to the streets. She eventually uses these connections to the street to help her old friend Selina, becoming something of a sidekick for her.
Holly reveals that she's a lesbian, with the storyline surrounding this becoming renown within comic books. She also later kills an old enemy of Catwoman's in order to save her life, which has a traumatic effect on the young woman. Needing a break from the mean streets of Gotham City, she trains with Ted Grant and travels the country with Selina. Afterward, she reunites with her long-lost brother and begins to look after local wayward kids.
During the events of "One Year Later," Holly became the new Catwoman while Selina retired due to pregnancy. This sees her eventually become a wanted woman in connection to the death of a woman killed by assassins gunning for Selina Kyle. She would briefly return to prominence when she began staying at a women's shelter. There, she befriends Harley Quinn and the two briefly become new Female Furies until Queen Hippolyta and Mary Marvel convinced them to leave. This story tied into both Amazons Attack! and Final Crisis. Returning to Earth after briefly gaining superpowers, Holly wouldn't really be seen again before Flashpoint.
The Post-Rebirth continuity greatly changes her adult status quo, when she killed an entire cell of terrorists who destroyed her former home. The crime is almost pinned on Selina, with the now well-trained Holly escaping the country before Batman can apprehend her. Before this, however, she was around for Selina's planned marriage to Bruce Wayne. Changing her name to Catherine Ann Turley, Holly's now in a place where she'll likely never be a close confidant to Selina Kyle ever again, making her a far cry from being Catwoman's Robin.