Hopefully you're all caught up on the second season of The CW's Arrow, because they're already setting their sites on the next season. (If you're not, check out our episode recaps here.)  After Team Arrow managed to subdue the threats that plagued Starling City in their sophomore season, one of the casualties came in the form of Oliver's younger sister, Thea (Willa Holland).  Physically, she's fine; but mentally and emotionally, she's turned her back on her friends and family, only to join up with her dastardly daddy, Malcolm Merlyn (John Barrowman).  Expect to see a lot of this daddy-daughter duo in season three, because Barrowman has just joined Arrow as a regular.  Hit the jump for more.

According to THR, Barrowman, who's popped up as Malcolm Merlyn/Dark Archer from time to time in the series, will be a series regular in Arrow's third season.  In addition to their write-up (and the new season three synopsis below), star Stephen Amell clued fans in to the change over social media:

Stephen Amell @amellywood #Arrow has a new series regular. @Team_Barrowman -- What could go wrong?!?! pic.twitter.com/VgFQdQhKNq

This definitely shakes things up for the third season, but you can expect many more villainous visitations to the show if its prior seasons are any indication.  Check out the official synopsis for season three of Arrow below (via CinemaBlend):

After a violent shipwreck, billionaire playboy Oliver Queen (Stephen Amell) was missing and presumed dead for five years before being discovered alive on a remote island in the Pacific.  He returned home to Starling City, bent on righting the wrongs of his family and fighting injustice.  To do this, he creates the persona of the Arrow and allies himself with former military man John Diggle (David Ramsey), computer-science expert Felicity Smoak (Emily Bett Rickards), street brawler Roy Harper (Colton Haynes) and international assassin Sara Lance (Caity Lotz), while keeping his secret from those closest to him including his sister Thea (Willa Holland), who has allied herself with his most deadly enemy.  Rivalries and allegiances will shift as Oliver faces his most difficult challenge yet.