In Outlander, Tobias Menzies actually plays two characters: Black Jack Randall and Frank Randall.
In Jamie’s world, Black Jack Randall is a dark and angry man who takes what he wants through rape and brutality.
By the time of the Season 2 finale, however, we knew Black Jack Randall was preparing to fight at the Battle of Culloden where he–books spoiler—dies in Diana Gabaldon’s series.
So, the fact that the actor will be back for Season 3 is actually quite significant and it says a lot.