Katie Cassidy Returns to 'Arrow' as Black Siren, Joins as Series Regular in Season 6

Damian Holbrook
Dean Buscher/The CW

Katie Cassidy debuted her Black Siren on 'The Flash.'

You heard that right, folks. Original cast member (and Season 4 casualty) Katie Cassidy is returning to Arrow as a series regular for Season 6, and she's bringing the Black Siren back with her.

Having been mortally shanked by Damien Darhk (Neal McDonagh) during his prison escape last year, the show's second Black Canary—after sister Sara (Caity Lotz), now on Legends' White Canary and before new recruit Dinah Drake (Juliana Harkavy)—a darker Laurel first popped up on The Flash as Black Siren, the ultra-bitchy and therefore delicious Earth 2 meta-human, before turns on Legends and Arrow. Now, she is slated to appear on the mothership's last 2 episodes of the season and then suit up full time next season.

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"One of the things that most excites us about Arrow is that we go where the story takes us," says executive producer Marc Guggenheim in a statement released by Warner Bros. "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 DC’s Legends of Tomorrow this season show, she never really left the family."

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After watching this exclusive sneak peek of Monday's episode, we already don't trust her.

The question is, will she leave her villainous ways behind her and join Team Arrow? After all, it's not like she plays well with others (ask Felicity), and the last time we saw Siren, she was being carted off to ARGUS so Oliver (Stephen Amell) could keep a close eye on his dead ex's evil twin.

What do you think? Is Black Siren's return to Arrow reason for alarm?

Arrow, Wednesdays, 8/7c, The CW