During the No Man's Land storyline in the 1999 Batbooks, Cassandra Cain, the trained daughter of assassins David Cain and Lady Shiva was given the role of Batgirl under the guidance of Batman and Oracle. In 2000, she became the first Batgirl to star in her own comic book series. The series ran until 2006 and Cassandra Cain abandoned the role of Batgirl shortly thereafter. She rejoined the Batman family as Blackbat, but was basically removed from continuity, aside from in New 52: Future's End where she is seen as a future member of the League Of Batgirls.
Stephanie Brown took over the Batgirl role after Cassandra Cain. Daughter of Cluemaster, she first appeared as Spoiler in 1992, later becoming Robin and then Batgirl. She starred in her own Batgirl series, the second to do so, from 2009 to 2011. Her continuity was then wiped out by the New 52 as Barbara Gordon became the only Batgirl and, despite many fan campaigns, she was kept off the board, and indeed DC executives believed the character was 'toxic'.
Cassandra Cain returned to regular continuity in Batman And Robin Eternal in 2015 as Orphan and as part of the DC Rebirth relaunch, became part of a team of Gotham vigilantes led by Batman and Batwoman in Detective Comics. But no Batgirl for her, Barbara Gordon has filled that role since the New 52.
The character returned as Spoiler in Batman Eternal, removing any time she had spent as Robin or Batgirl, and also joined the team of Gotham vigilantes in Detective Comics for the DC Rebirth. However, since then, it has been established that, yes, Stephanie Brown was Robin for a short time – but not Batgirl.
Right now they both operate as Orphan and Spoiler respectively. But Bleeding Cool has learned there are big changes planned for 2021. Specifically that Cassandra Cain will be Batgirl – for the first time in current DC continuity. Full mask costume, batcape and yellow-outline batsymbol, the lot. And that while Stephanie Brown will remain in the Spoiler look, purple, facemask and cape – she will sport the Bat symbol in her new look.
Previously in Detective Comics, the pair had a glimpse of what continuity had stolen from them both.
As well as the importance of a certain symbol to them both.
Now its time for both of them to wear it on their chests again, whatever they end up being called.
Keep an eye on the DCComics2021 tag on Bleeding Cool over the next couple of days for more of this sort of thing, before DC Fandome makes it open season.