I also think we will see the female terrorist who received the presidential pardon back as a villain.
Since she was in every season except 3, I think that's a good bet.
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She may be back as a villian, but I don't know if she'd be able to have a bigger role. The actress plays a main character in another show - one that I'm fairly certain most people on here don't watch.
I don't know if Showtime is like HBO, but there tend to be long breaks between new series on HBO. Didn't the Sopranos take like 18 months between seasons?
The point being that an actress could very well schedule being in both a newtwork show and a Showtime series.
SD