The cast for "Arrow" season 4 is building up with an actor finally cast to play Mr. Terrific. The recurring role has been snagged by Echo Kellum, who fans know as Tommy in "Ben and Kate." The character's alter ego is Curtis Holt and he will be working with Felicity in the new season. 

Mr. Terrific, as revealed during the San Diego Comic-Con, is a gay character. As Comingsoon.net notes, he was presented in two versions in the comics but the more popular one has Michael Holt, a celebrated athlete who has T-Spheres for crime-fighting gear, as his alter-ego. 

Anarky, another character in the comics confirmed to get a small screen counterpart in "Arrow" season 4, will be played by former Nickelodeon star Alexander Calvert. Often a villain to Batman, this baddie will be helping out Damien Darhk (Neal McDonough) to execute his evil plans. 

Speaking of Damien, Entertainment Weekly said that the baddie will be the reason Oliver will be roped back to Starling City.

"He entrusted Laurel, Diggle and Thea to mind the fort. Damien represents a threat that three heroes are not enough to combat," executive producer Marc Guggenheim told the site. 

The showrunner described Damien as "not nearly as moral" and "pure evil" who has no other motivation for his crimes other than being entertained.

"That's what Damien represents. He's the prince of darkness," he said. 

Meanwhile, executive producer Wendy Mericle has also raised the possibility that another DC Comics character in the form of occult detective and sorcerer Constantine will appear in "Arrow" season 4. The character had its own series in NBC but it didn't last longer than one season. 

"Arrow" actor Stephen Amell was one of the many who came to the defense of the cancelled show. He promised that if a network renews "Constantine" for another season, he will guest star as Oliver Queen. This effort was deemed in vain until now. 

"Yeah, we really want to do it," the EP told IGN. "It's something we've been talking to DC about and it's just a question of some political things, but also the actor's schedule. We're trying to work it out, but we don't know 100 percent if it's going to happen." 

"Arrow" season 4 is scheduled to premiere Oct. 7.