Ruby will play DC's most popular gay character.
In the comic books, Batwoman has a long history and epic. She first appeared as a love interest for Bruce Wayne in the 1950's after censorship reached an all-time high. At the time, a book called Seduction of the Innocents by Dr. Fredrick Wertham suggested that comics were teaching children about violence, and he also argued that they promoted homosexuality. Wertham used Batman and Robin, a man and a boy who run around in tights together, as an example of the homosexuality in comics. In an effort to quell parents concerns at the time, DC Comics created Batwoman.
Batwoman was later reinvented as a gay character herself in the mid 00's. She went from being used to stifle the fears of gay characters in comics, to being the face of the LGBT movement at DC. Now that's progress. According to a press release from DC, Ruby Rose has been cast to play Batwoman in a new Arrowverse crossover event. The Arrowverse crossover event will bring heroes from all of The CW's DC shows together. That includes Supergirl, The Flash, Arrow, Legends of Tomorrow, and Black Lightning. The crossover events began with "Flash vs. Arrow" in 2014 and the last multi-show storyline "Crisis on Earth-X" premiered last year.