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Tain is back again on “DS9.”

Introduced in the second-season episode “The Wire,” Tain is the enigmatic head of the Obsidian Order, Cardassia’s CIA. Now, he returns in the two-episode arc “Improbable Cause” and “The Die Is Cast,” airing over the next two weeks.

And buried anew beneath four hours’ worth of makeup is actor Paul Dooley, best known for his roles as the fathers in “Breaking Away” (1979) and “Sixteen Candles” (1984).

More recently, Dooley seems to have become ubiquitous, with recurring roles on “Dream On,” which earned him a 1994 Emmy nomination, “My So-Called Life,” “Grace Under Fire” and “DS9.”

“Tain is a Cardassian William Casey, the ex-CIA head,” jokes the chatty Dooley during a phone conversation from his home in Toluca Lake, Calif. “He’s interesting because you can’t get a handle on him.

“One minute he’s your friend and the next he’s coldblooded.”

In Dooley’s first “DS9” outing, Garak (Andrew Robinson) became addicted to a painkiller implanted in him by Tain, Garak’s former boss. Bashir (Siddig El Fadil) ultimately secured from Tain the information needed to save Garak.

Along the way, it was revealed that Tain was Garak’s mentor, but that he’d also exiled Garak from Cardassia.

Now, in “Improbable Cause,” Garak is in trouble again. An assassin has bombed his store. While investigating, Odo (Rene Auberjonois) discovers that the explosion was merely an element of a Cardassian-Romulan plan to destroy the Dominion.

“Tain tried having Garak murdered because he knew too much, but by the end Garak is back in the fold and Tain tells him about the plan to eliminate the Dominion,” Dooley reveals.

“That sets up the second episode.”

The 66-year-old actor won’t reveal much about the twist-heavy “The Die Is Cast.” Suffice it to say the Founders may not be as vulnerable as their attackers believe.

“I can tell you Tain’s fate is a cliffhanger,” says Dooley. “They can bring him back or say he died.”

Apparently, the only drawback to his “DS9” experiences was the long hours spent filming “Die.”

“That was 20 hours, four in makeup and 16 working,” he sighs. “There wasn’t much time between shots and there were no scenes I wasn’t in the day I worked.

“It was tough, but if the show turns out well, which I think it will, it’ll have been worth it.”

Born and raised in Parkersburg, W. Va., Dooley spent his career’s early years on Broadway and off-Broadway stages. Between jobs, he performed stand-up comedy and worked as a magician and clown.

He later performed with the Manhattan branch of the Second City comedy troupe, and got his big break in the original Broadway production of “The Odd Couple.”

Countless television and radio commercials followed, as did such films as “Death Wish” (1974), “Popeye” (1980), “Flashback” (1989) and “The Player” (1992). Perhaps Dooley’s most intriguing credit is the PBS children’s program “The Electric Company.”

“I basically created that program and was its head writer,” he says. “I’m proud of that show, and people still talk to me about it all the time.”

Between appearances on his series, he completed roles in the upcoming Steven Soderbergh thriller, “The Underneath,” the films “Evolver” (about a robot run amok) and “Out There” (a sci-fi spoof) and the ABC-TV remake of “The Computer Wore Tennis Shoes.”

In addition, the actor frequently joins several friends, who bill themselves as “The Post-Modernaires,” for evenings of improvisational comedy.

Finally, there’s family to make time for, including his wife, “My So-Called Life” creator Winnie Holzman, their daughter, Savannah, 9, and Dooley’s three adult children from an earlier marriage.

“I`ve had a good career and life,” he says. “I’ve gotten to do a bit of everything, really, so I consider myself quite lucky.”

CON CALENDAR: Saturday-Sunday: Creation at the Congress Center in Toronto, featuring Brent Spiner. (818-409-0960.)

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