Warning: Plenty of spoilers for the current season of Arrow...
Season five of the much improved Arrow still has several episodes left in its current run, but plans are already afoot for season six and one new series regular has been confirmed; Katie Cassidy. Despite Laurel Lance being killed at the hands of Damien Darhk in season four, Cassidy has since popped up in season two of The Flash and the Arrow mid-season opener as evil metahuman doppleganger Black Siren from an alternate Earth.
According to The Hollywood Reporter, Cassidy will be returning as Black Siren - last seen imprisoned by Oliver Queen - in the final two episodes of season five and then play the character as a series regular for season six.
The show's executive producer Marc Guggenheim made the following statement:
"Last year, the story took us to the tragic death of Laurel Lance. This year, our midseason finale reintroduced us to Laurel’s doppelgänger, Black Siren. We were so taken by Katie’s fearless interpretation of this character that we knew her story was not yet finished. We couldn’t be more thrilled to welcome Katie back to Arrow as Black Siren, though as her appearances on Arrow and Legends of Tomorrow this season show, she never really left the family."
Guggenheim also spoke to Screener TV about recurring series villain Vigilante. In the comics he was the alter ego of Adrian Chase who was recently unmasked as season five villain Prometheus. As such, Vigilante's identity continues to remain a mystery and will do until season six.
“We know who it is, but we were kind of intrigued by the idea of having a mystery that led into the next season. We were excited at the prospect of just letting this play out for a little while longer, and it gives us something cool to do in Season 6.
“As a general rule, I’m not a fan of mystery characters who when you take off the mask the audience goes, ‘What a minute, I’ve never seen that person before in my life. I’m probably not spoiling anything by saying whoever’s underneath the Vigilante mask, you’ve seen that person before.”
In the meantime, you can follow Baz Greenland's weekly reviews of Arrow with the latest review Checkmate here.