Arrow Season 2 Spoilers: First look at Harley Quinn and Deathstroke's army?

Season 2 of the CW's Arrow is roaring ahead, but it looks like things are about to get a whole lot more chaotic before the season ends.

Firstly, Michael Rowe, who plays Deadshot on the show, posted a behind-the-scenes Instagram photo that features the entire Suicide Squad, including Cassidy Alexa as Harley Quinn (the Joker's sidekick). Fans had already seen the back of the character, who was played by Alexa and voiced by Tara Strong. But it seems that her proper introduction is upcoming.

Earlier this month, the "Matt's Inside Line" column at TVLine fielded a question this week about the girl with pigtails who appeared in the promo for the episode entitled "Suicide Squad."

"I'm a huge Arrow fan and I was wondering if you had any hints about the mysterious girl (with the pigtails) in the "Suicide Squad" promo? -Celeste
The CW has no official comment - and I'm hearing it's possible this mystery woman won't appear in the actual episode - but our good friends at IGN are speculating that it's a veiled nod to Harley Quinn."

Secondly, this Twitter account posted a set photo from the filming of Episode 22 entitled "Streets of Fire." The picture appears to show a masked army, presumably working for Deathstroke, overrunning the streets of Starling City.

What do you think Harley Quinn's introduction means for Arrow? Could we possibly see other Batman villains appear? And what does this Deathstroke army mean for the show as Season 2 nears its end? Let us know your thoughts in the comments below.