The fourth season of Supergirl adds The Walking Dead's Xander Berkeley as Agent Liberty's father. Kara Danvers most recently defeated the Worldkillers, but a completely different storyline will be at the center of season 4. Season 3 ended by showing the Russians finding another Supergirl (Melissa Benoist), teasing an adaptation of the Red Son Elseworlds story from DC comics, but focused on Supergirl instead of Superman for the small screen.
However that storyline plays into things, season 4 will also deal with Supergirl's fight with Agent Liberty. Sam Witwer joins Supergirl to play the new villain, and it appears the show will be diving into Ben Lockwood's personal life outside of his time as a masked supervillain.
TV Insider reports Xander Berkeley has joined Supergirl season 4. He'll play Agent Liberty's father, Peter Lockwood. The casting announcement for Berkeley describes the elder Lockwood as "a middle-class factory owner struggling to make ends meet in a world that’s rapidly changing due to the rise of aliens from outer space living amongst us." Additionally, he's said to be "a family man who’s dedicated his life providing for people. The seeds of his discontent sows the beginning of an anti-alien wave."
Playing an antagonist is nothing new for Berkeley. He currently plays Gregory on The Walking Dead, and is constantly a source of trouble for the Hilltop. He was also one of the main villains in Nikita, and also played one on 24 and The Mentalist. If his past work is any indication, he'll easily slide in to the Arrowverse as a secondary antagonist. And if he's where Agent Liberty gets his agenda, then he could play a pivotal role throughout the season. There's no details at this time in regard to how many episodes he'll appear in.
Berkeley is just the latest cast member to join Supergirl season 4. Anthony Konechny was recently announced to be joining the series as a new DEO agent. Bruce Boxleitner also joined the cast to replace Brett Spiner as Vice President Baker. Rhona Mitra was cast as Mercy Graves, a character with strong ties to the Luthor family. There's been a variety of other castings made as well, but none may be as noteworthy as Nicole Maines landing the role of Dreamer, the first transgender superhero in TV history. Expect more casting additions to be announced as the fourth season continues to film. As the cast does continue to take shape, hopefully more details on just how much Berkeley is involved in the story will be revealed too.
Supergirl season 4 premieres October 14 on The CW.
Source: TV Insider