TV Guide Magazine has learned that Spiner will join the Syfy series July 23 (the Season 4 premiere) for at least six episodes as Brother Adrian, leader of a top-secret sect known as the Brotherhood of the Knights of the Black Diamond.
The plot picks up after the show's explosive Season 3 finale, during which the warehouse was destroyed and several top characters were killed. "Artie Nielsen [Rubinek] and the gang are on a mission to pull their lives back together and Brother Adrian is a major obstacle to that," says executive producer Jack Kenny. "The Brotherhood is descended from the Knights Templar and connected to the Vatican. It is charged with the protection of many powerful artifacts, one of which Artie desperately needs to make everything right again."
There's just one problem, and it's a biggie. "The use of this object will unleash an incredible evil and Brother Adrian is not about to see that happen," says Kenny. "He heads a sect that is powerful and obsessively devoted and follows no rules. The Brotherhood will do anything to achieve its goals. They are gifted fighters who are willing to go to their deaths, if necessary.
Read more at TV Guide
