The first description of Batwoman in the Arrowverse might've been revealed thanks to the casting breakdowns for Arrow season 7. Back in May, during CW's Upfront presentation, Arrow star Stephen Amell revealed that the next annual Arrowverse crossover would bring Batwoman and Gotham City to the TV multiverse. Since that bombshell, details on why Kate Kane's alter ego would even show up have been scarce.
It's even been unclear if Batwoman will pop up on one of the handful of Arrowverse series before the crossover and if so, which one. There's been evidence for Batwoman and Gotham to exist on Earth-1 of Arrow and The Flash or Supergirl's Earth-38. The newest casting information makes it seem like the Bat wind is blowing in Arrow's direction. Kate Kane could appear on the universe's flagship series before the crossover event.
That Hashtag Show has received the breakdown for three new characters that will join Arrow during season 7. The first couple, a 30-40s "intimating" male named "Dover" and a 30-something female mercenary named "Leah" aren't all that interesting. It's possible that Leah and Dover, who are both recurring, could be code names for important DC character and/or just become hugely influential figures in Arrow season 7. Neither though is likely to be Batwoman.
The third new character who is being given the name "Angeline" (for now) is a lot more intriguing. Angeline is being described as a diverse woman in her 30s and fierce fighter despite "a small stature." Angeline is experienced in stealth and able to "wipe out buildings filled with foes all by herself before she is gone like a ghost." Angeline thinks very highly of her abilities and will be recurring presence in Arrow season 7. The description doesn't exactly scream Batwoman but it hints at her rather heavily.
Batwoman isn't known for being small in stature. She's usually depicted as being as a similar height and body type to her cousin, Batman. However everything else would be a rather natural fit for Batwoman. There's few DC heroes that can wipe out an entire building and escape "like a ghost" better than members of the Batfamily.
Even if Batwoman makes her debut in the yearly Arrowverse crossover it would make sense to introduce her civilian identity, Kate Kane, before the event or one of the Arrowverse shows. Arrow would be the most natural fit for Batwoman to make an appearance as the show usually hits a lot of the same themes as a regular Batman story. Star City will also be without its main vigilante of the night following Oliver Queen's arrest in season 6. Angeline (or Batwoman) could arrive to fill that hole.
This is all speculation, of course. Yet it seems rather undeniable that whether Angeline is Batwoman or not that she will be some new type of hero or vigilante on Arrow. She could be an original character or some other DC hero that stalks in the shadows that's not Batwoman. However, with Team Arrow already being rather stuffed and Batwoman's arrival to the Arrowverse a certainty, it only makes sense to connect the two dots.
Batwoman could never appear on Arrow in any capacity and just be apart of the crossover event. Yet the smart money is on Angeline being a codename for none other than Kate Kane. For now though fans will have to wait to learn for sure. Although it's likely that more Arrow season 7 details will come out at San Diego Comic Con in late July.