The actor will play a very important role on the DC-based series
"Once you let the darkness inside, it never comes out," the trailer begins ominously
He will play a mysterious scientist and busines man named Ray Palmer, aka superhero The Atom, in season three
TheWrap has first look of the streaming network's hit series which returns in April
The "X-Men" filmmaker also offered his thoughts on Zack Snyder's "Man of Steel"
The "Scott Pilgrim" actor will star in "Missing William" with his real-life wife Courtney Ford ("Dexter")