Black Siren Strikes Again In New 'Arrow' Promo

The CW has released a new promo for 'Reversal', the upcoming fourth episode of Arrow's sixth season.

The promo shows the return of Laurel Lance/Black Siren (Katie Cassidy), and it looks like she's back with a vengeance. Siren is seen meeting a guy in a bar in a black wig disguise, before hooking up with and killing him.

This catches the attention of Team Arrow, who appear to take the fight to some sort of tech warehouse. While it's unclear exactly what Siren wants there, she ends up facing off against John Diggle/Green Arrow (David Ramsey).

This is the second time the fan-favorite villain has been seen this season, after first appearing in the Season 6 debut. With Cassidy returning to the show in a series regular role, fans can expect to find out even more about Siren - possibly in this episode.

"Yes, I think the more we learn about her backstory and what her relationship was like with Oliver, absolutely." Cassidy told ComicBook.com earlier this year. "I think it will make sense in the end and not necessarily make her as bad of a person. You might be like 'Oh, okay that makes sense.' Yes, I do think we'll know more."

Arrow airs Thursdays at 9/8c on The CW.