According to a TVLine report Tom Amandes has been cast to play DC Comics villain The Calculator in season 4 of Arrow.

Death In Premiere Is Not 'A Fake-Out,' Showrunner Dishes   

Amandes is set to play the villain who is known for is a en evil technical genius and will use his powers to blackmail Roy Harper (Colton Haynes) on the show. In fact the Calculator will be the reason for Roy's return.

Amande has worked with Arrow's executive producer Greg Berlanti's other projects like Everwood, Eli Stone and No Ordinary Family in the past.

John Barrowman Teases 'Jaw-Dropping' Twist Spurred By Nyssa   

Haynes also recently announced his return on Arrow via Twitter. He expressed excitement about being back in Vancouver to begin filming for his parts in the show.

In other news of guest stars returning in the rest of the season, Nyssa al Ghul (Katrina Law) hasn't quite left the building yet.

Fans were left wondering if Nyssa will be coming back this season after she was put behind bars. Arrowshowrunner Wendy Mericle confirmed to TVLine that Nyssa will indeed be coming back as she has unsettled business.

"Nyssa's stories are far from wrapped up," said Mericle. "She's in Nanda Parbat, she's been arrested in the wake of destroying the Lazarus Pit, and she has a score to settle with Malcolm Merlyn. We don't intended to leave anyone hanging, including her!"

So Merlyn (John Barrowman) should brace himself as his troubles on the Nyssa feud front are not quite over yet.

In a previous interview with TVLine, Mericle had spoken some more about Merlyn's character arc when it comes to Nyssa.

Nyssa will not be at peace about Merlyn claiming what was assumed to be her birth right, playing heiress to Ra's al Ghul. According to Mericle, Nyssa is "definitely not going to be on board with Malcolm as Ra's." This animus will lead to some fighting: "We're hoping to take that in a cool, very fighty-fight orientated direction."

The next episode, titled 'Legends of Yesterday,' will air on Dec. 11 on The CW.