Thisjust in: According to an article on tvline.com, Neal Mcdonough has been cast as the villianous Damien Dahrk
on the 4th season of Arrow.
Mcdonough is a very well known actor who has been in movies like Timline (2003), and Paul Blart: Mall Cop 2 (2015). He has also had a recurring role in the marvel cinematic universe playing the role of Howling Commando Dum Dum Dugan in Captain America: The First Avenger (2011) and Marvel's Agent Cater (2015).
According to the article on tvline.com the Arrow producers are saying that the character is “a mysterious and sophisticated villain, and an adversary of the late Ra’s Al Ghul. Now the leader of his own clandestine group, this cunning foe will prove to be one of the Arrow’s greatest challenges.”
I for one am very excited about this casting choice and can't wait to see him kick major butt as Damien Dahrk.