For the above-described reasons, I will also omit any spoilers and simply say: Duh.

It's either Roslin or Starbuck (which would be disappointingly obvious). My own wild theory is that it is the dead, or "dead", Adama brother.

Remember that Roslyn's cancer was cured the first time with... a blood transfusion from the Cylon Boomer.

So say we all?

@3: Close, but not from Boomer.

I'm expecting it will be someone less obvious, frankly, and perhaps a returned character so we'll know immediately: Admiral Cain would be my first vote for dramatic impact. Billy could possibly do it, too, which would make another kind of sense if they're programmed to seek out positions where they can influence those in power.

Nope, not Roslin or Starbuck:

"Contrary to fan speculation, Moore swears it isn’t one of the show’s primary humans. Not Starbuck or President Roslin. Not Admiral Adama (Edward James Olmos) or his son, Lee (Jamie Bamber). Or even the ever-dubious, Cylon-shagging Gaius Baltar (James Callis). “Even if you guess correctly, it’s still just a guess,” Moore says. “There’s no way anyone can figure it out without knowing exactly where we’re going with the final season."

http://seattlepi.nwsource.com/tvguide/357752_tvgif4.html

What about Adama himself? The Razor (episode? movie?) had him invading a Cylon facility built especially to create human-like Cylons.

I think it's Chef in the Cafeteria.

i'm going to guess Jack...or Sayid...or Hurley.

shit, wrong geekfest!

So is this to say that the Cylons timed the attack so that Roslin would be in transit and not on Caprica, so that she would be the only one left in the government? Wasn't she like 30th or something in the line of succession? I supposed if you own the network, you can make sure you kill everyone who's ahead of her and make sure her transport isn't attacked. Makes sense I guess.

And if she's the Cylon, and there can be multiple copies, that would be good because Mary McDonnell is smokin' hot even though she's like 10 years older than I am.

I haven't re-watched BSG, but I haven't seen any evidence in or out of the show that the producers knew the identities of cylons 8-11 very long before they were revealed.

Lots and lots about the identities of 8-11 bug me, and not just that it undermines so much of Tigh's brushes with alcoholic oblivion, or that the New Caprican leadership turns out to have involved few humans on either side. That Tyrol and Tigh happened to be serving on the same ship almost implies that Galactica was spared on purpose, which seems logistically implausible, especially given that the Cylons have spent three seasons trying fairly hard to kill them. And how would they have been able to count on Anders serving any useful role whatsoever, being stuck on Caprica taking potshots at centurions? That he made it to Galactica was never predictable, unless Kara's the twelfth, which would be boring.

That at least three of the five were in the human military suggests it would have been hard to introduce redundant copies, at least within the military -- a tight-knit community would recognize repeated faces, and there'd be a greater likelihood of genetic databases even in the face of the humans' technophobia (maybe mere network-phobia) evident in the early episodes.

So, Tori could maybe have been hidden anywhere, but how could the Cylons count on the other three's survival? The end of last season felt a lot like the X-Files' latter years where they were clearly making unplanned shit up, and the first couple episodes of the new season haven't made that feeling go away.

I do appreciate that Baltar's adorable new concubine is played by an actress named Leela, symbolically bridging television's two best sci-fi shows (or three, if you care to count Doctor Who).

But her cancer has returned. And also I would be really annoyed if they picked yet another character who is 100% anti-cylon and made them the final one. Which is why I think it isn't Starbuck either. Besides, all the Cylon ladies are young and smoking hot so it can't be Roslin. I think it's Gaeta.

Other reasons Roslin is a good candidate:

-In season 3 finale she shares a vision with 6 and Athena, to which 6 exclaims "that shouldn't be possible", and gives Athena a questioning look.

-Also in 3 finale, Roslin gasps right before the power dies on all the colonial ships.

-Each Cylon represents a cross section of humanity... the only archetype glaringly underrepresented is a matronly figure.

-Making Roslin a Cylon would in turn make her relationship to Adama a fitting metaphor for the overall theme of the show: The love/hate relationship between Humanity and Cylons.

-In a promo for Season 4, you can clearly see Roslin aboard a Basestar.

But if she's not the 12th Cylon, my next guess is Tom Zereck. Seems like all the Cylons thus far of managed to move themselves into positions of power, and no one has done that more so than him.

@11: Divine intervention. The cylons want to act in ways that please God, but of course don't know what exactly he has in store. The only reason that 8-11 have lasted for as long (and together) is because their God has been protecting them.

Making Roslin, Adama or Starbuck cylons is an incredibly cheap cop-out. I'd like to see it be Zarek, since that would be a sort of throwback to the original series as well.

This proves that we're all geeks. I get giddy when I read "cylon".

Also, my money is on the dead Adama brother.

According to the show's creator, Ron Moore, "In an interview with Entertainment Weekly, Moore claims that the final Cylon is not on display in the promotional poster for the fourth season. Since the poster contains almost every major character in the "Galactica" universe, including Starbuck, Adama, Apollo and Roslin, this leaves us with either an as-yet-unknown Cylon character or a supporting character Cylon." -- Salon.com

Nat @11: I can't find the interview now, but you're right about them coming up with the identities of the final 5 fairly recently. They had to brainstorm which characters could plausibly make sense, and Tory was the only obvious one because she's the only one without a past, really. This kind of bugs me too, but I have hope that they can make it work.

As far as the Cylons sparing the Galactica because of Roslyn, Tigh, and Tyrol: they didn't know they were there, or even that they're the final models, so it really is all the more serendipitous that they lived. My guess is that it's all about the fate/destiny/God stuff that's going on. And I don't think there are copies of the final 5. I think they only have the body they're in, but I guess we'll see.

My vote for the last Cylon would be Doc Cottle or Admiral Cain. I really hope it's Cain.

Other things to keep in mind about the final 5:

-The other Cylons erased them from their collective memory for reasons unknown... hence Diana Biers killing herself over and over in order to glimpse them as she downloaded.

-All the final four seem hell bent on helping humanity, which would explain them taking such high ranking roles in the insurgence, and voicing strong anti-cylon views.

Knowing these two things, I hypothesis that the final five were the first to propose co-habitation with humanity, and as a result #1 boxed them and erased all memory of their existence... leaving only those that had not yet died and attempted download to survive.

...And now I'm done geeking out.

#11 -- if it really does turn out to be "divine intervention", I'm going to be pissed.

The problem with cylon #12 being Adama's other son is that presumably he was a person whom other people observed emerging from a vagina, gurgling incoherently for a long time, going to preschool, growing up, etc. That's not how the cylon stork operates.

@19 - I hope it's not Doc Cottle, that's just one too many gruff Cylons for my taste.

Oh come on, It can't be cain.

every one of the cylons has an interspecies relationship at one point. Cain was munching on Tricia Helfer, so She is in the clear.

It is so obviously Tom Zarek. Get with it people.

Racetrack, Racetrack, Racetrack....

(and I'll refer back here when I'm right!)

#23 -- I don't think interspecies relationships are really much of a deciding factor, but I can't recall Tori boinking anyone except Anders.

It's so obviously got to be Boxey.

Nope, Tori is getting Baltared now.

@25 : She got on her back for Baltar, to suss out whether he is a Cylon or not.

We've never seen the circumstances of brother Adama's "death", and we have already witnessed the apparent death and resurrection of another character. Who's to say his "training accident" wasn't orchestrated by the Cylons, and a new model put in place?

Additionally, who's to say what the nature of biology of the final 5 is? We've seen two babies that we now know to be products of human-Cylon boinking. What if that is the source of creation of the final 5?

It's a vagina not a cylon detector.

My other guess was that it was Ellen Tigh, since there was Chief/Boomer and Tori/Anders boinkage. Tigh is the only one left out of the fun.

I got yer number 12 right here: Tigh's dead wife. Just you wait.

that's a robot vagina. who knows what modifications it has undergone.

It's either Zarek or Ellen Tigh, though I'm going with Zarek.

My guess is that the "Final 5" only come one per model, unlike the other cylons, and that their agenda is not the same. So you can't point out inconsistencies with overall cylon strategy to discount certain choices.

Another guess, consistent with a larger theory I have that's too geeky to get into except by inference, is that the Five might not have a fixed form. They might be genetic programming passed down through the generations to be triggered at the appropriate time ("This has all happened before.") So every one of the Five probably was born and lived as a normal human until entering the nebula. This might also allow for some kind of mini-resurrection whereby even if the host human body dies, the cylon programming can be transferred or activated in another human. Maybe the programming is inherent in ALL human DNA, and the nebula simply chooses five to activate from the fleet during each historical cycle. This also allows for a retcon to explain that Billy was likely one of the Five until he was killed for "actor gets a better job" reasons. Similarly, perhaps Ellen was fated to be one of the Five until she was killed, with Tigh taking her place.

The final cylon has to be someone who wasn't able to meet the others on Galactica. So it can't be Roslin or Apollo or Adama or Baltar or Doc Cottle, who were all aboard and available to show up. That leaves Starbuck (too obvious), or a second-tier character on another ship. Ellen's dead, so unless there are multiple Final Five copies, the good money is on Zarek.

Ellen Tigh sounds like an interesting choice, as would Zarek, if it's official that Starbuck & Roslin are out.

I've been suspecting Starbuck for a while, because she's so conspicuously, stronger, faster,smarter, tougher than average, as well as having such a predatory disregard for life, especially her own. Add to that that she's managed the feat of coming back from the dead like Jesus, and it's just too good a case. Might as well give her a morning coat and striped pants, call her Jeeves, and send her for wine.

It CAN'T be the late Zack Adama. His father knew him from childhood. Lee knew him from childhood. Cylons don't get childhoods. They're born as young or middle aged adults.

So, here's my theory:

"Life here began out there."

"This has all happened before, and it will happen again."

What I think is that Earth is actually the origin of humanity, not Kobol.

The 12th Cylon model is actually collectively all humans: Model 12 is the only model that can reproduce and have genetic variability and take on the diversity of appearance that humans normally exhibit. So anyone on BSG who is not a Cylon Model 1-11 but is otherwise "human" is actually a form of Model 12.

In each cycle of history, humans develop sentient "robots" (or artificial life forms, like the Cylons), who eventually rebel and take over. These life forms then eventually evolve and come to believe that they are "humans," forgetting their true origins. Humans have actually long died out--or evolved themselves into something analogous to the Beings of Light from the original series.

How could it be Colonel Tigh? Hasn't he already been revealed as one of the final five? You do mean the guy with the patch over his eye, don't you?

@36

I assume you're question refers to the theory of 12 being Ellen Tigh (who is Colonel Tigh's dead wife.)

@35: Consider my mind blown. HOLY CRAP WE ARE ALL CYLONS!!!

ok, now I'm wondering if it's Gaeta ...

35 has the best theory I've heard, yet.

Also, this wins for SLOG post of the month.

Simac's theory @35 is pretty good, I have to admit. But put it side by side with my Boxey theory. Look at them both. Objectively.

Eh? See what I mean? Eh? Boxey is looking pretty good, ain't he?

@35 seems a bit matrix-y for my taste... if that's the case, I half expect the 12th cylon to be the architect.

And, did the robot Cylons kill all the copies of the Three? Or did they only kill them once ... for dumbing them down. Questions, questions.

But @35 gets the win.

@35: Very interesting theory...

So in Razor, when the Hybrid said Kara would bring about the end of humanity, he wasn't referring to the fleet, but rather to the original humans.

By bringing the fleet to Earth and revealing the truth, she's going to break the cycle... which if you believe history should repeat itself over and over would be apocolyptic.

The final four were Cyclon models that deduced the cycle and got boxed for their trouble like the Threes. But they managed to reach out and manifest themselves in ordinary "humans"... which isn't that hard because everyone is a Cylon.

The Head-Baltar, Head-Natalie and Head-Leoben are Beings of Light - the original humans - trying to end the barbaric cycle of their children so that they can move on and eventually evolve like they did. But I think there's the possibility that they have differing agendas however, with Alt-Natalie having a more malevolent agenda.

Certain cylons models (the Ones, Fours and Fives) have invested themselves in perpetuating the cycle and will do anything to see that it continues. They'll be the primary antagonists at the end once the rest of the models ally with the fleet.

In the end, the fleet will settle on Earth and repopulate the species with the remainder of the Twos, Sixes, Eights and possibly Threes. (All the hot Cyclon models so lucky fleet.)

Dude, it's Bush.

well, it's someone on Earth. that's why Zena (warrior princess) couldn't believe it - she saw the final Cylon on earth. Think about it.......... the 4 on galactica have been trying to keep the other Cylons from following because they were programmed by the 12th to defend him/her and keep Cylons from Earth. and all knowledge of the final 5 was wiped from the rest to keep them from wanting to pursue the last 5.

Jon G, you're my science nerd God

I haven't read all of the comments, so I apologize if I'm repeating: it's Dee. My logic: it can't be anyone who was exposed to the Cylon virus, it can't be anyone who has family on the show, it has to be someone close to the center but can't actually betray the audience (not Roslin). I like Tom Zarek for it, but I think the balance of male to female among the Cylons is already too great. Finally, in that recreation of the Last Supper, the place where Judas should be is empty, the character should be leaning on Lee Adama and adjacent to Saul Tigh -- exactly where Duala should be.

Oh, and doubly not Baltar (virus exposure) because he appears in the Opera House vision with Hera at the same time that the Five are looking down from the balcony. Roslin also appears in that vision but disappears just before the Five arrive, which could mean anything but I think she dies.

(Yes I have spent too much time thinking about this, but at least I didn't rewatch the entire series from the beginning.)

Simac @35 is on to something.

Just to frak w/ everyone, here's what I've been noodling since season 3:

Why are there 12 Cylon models? Perhaps 'cuz its consistent with the 12 colonies?

But there are actually 13 colonies. And the post-apocalyptic fleet (made up of representatives from the other 12 colonies) is clearly re-tracing/living-out the destiny of the founders of the 13th colony: Kobol. Clearly, the fleet is destined to establish a contemporary 13th colony and restart civilization.

So why couldn't there actually be 13 Cylon models, with the 13th representing some amalgam of the others (a hybrid perhaps?).

So now we're looking for 2 remaining Cylons (a 12th and a 13th). Anyone know of two hybrids in the show? Why, that would be Hera & Nicholas...

Cylons are mass-produced clones. But Hera & Nicholas are each one-of-a-kind hybrids. What if they become the progenitors of the 13th colony and future civilization?

Just a thought...

AMD

Although I think that all humans are cylons is a cop-out, I think #35 is the closest. Finding the temple that they found on that abandoned planet is the biggest clue. It suggests that the final five cylons are very old very different from the other seven.

The cylon civil war that started last week must also be informative, given the repeated pronouncements that everything that is happening now has happened before and will happen again.

Okay, after giving this a bit of thought, I think I have to disagree with somewhat Simac, and put forth an alternate theory, which is my theory:

The 12 Cylon is already on earth.

Here's what I think will be revealed during Season 4: the "Final Five" rebelled against the idea of destroying all the humans on the 12 colonies; they essentially "exceeded their programming" in much the same way we now see occuring in the emerging conflict between the "Original Seven".

By rejecting the fundamentalist monotheism that lay at the heart of this decision, they created a schism that threatened the solidarity of the remaining seven models, and so were "boxed" in order to prevent them from influencing the others and interfering with the plan.

Realizing that other of the remaining seven models might eventually reach a similar conclusion independent of the Five, all knowledge of them was wiped from the memories of the Seven, although that knowledge has slowly been bleeding back, either due to faulty wipes, or other factors, such as repeated resurrections, which presumably puts the downloaded memories of a deceased model in temporary contact with the "master server" that still retains information on ALL the models, as evinced by some of the cryptic utterances from the base star "hybrids".

However, before boxing, the Five managed to encode instructions to protect humanity into any models still remaining on the colonies. Realizing that, as duplicate models died or were killed, they would not be resurrected, it was decided to "seed" a core group into strategic positions where they might prove most effective in protecting any survivors, if in fact the final annihilation could not be prevented.

The Five also surmised that the Original Seven would not stop until all humans had been eradicated, suspecting they would follow any escaping survivors into deep space. If this occured, it was simple to conclude the most logical direction for the remaining humans to proceed would be first to Kobol, and then, if necessary, to earth.

So, as a last-ditch back up plan, one of the Five, a model 12 Cylon, was given a mission: find Kobol, and then, if possible earth, planting clues along the most probable route as outlined in the scriptures, clues that would help direct the humans, without revealing too much to the Cylons. It is possible they felt eventually enough of the other models would come around to seeing the futility and immorality of their actions, that they might give up the pursuit, allowing the humans to rebuild their civilization, and that earth would be the most probable location for that to occur.

I believe the 12th Cylon has in fact reached earth, and is awaiting the arrival of any remaining human survivors. Somehow that 12th is now in contact with Kara Thrace (which may point to her being a 12), directing her, hence her ability to sense when the fleet is moving away from the correct route to earth.

I think the surprise we're going to get at the end of the season is something along the lines of an "Adam & Eve" scenario. We already know humans and Cylons can procreate, and we are now seeing evidence that Cylons have the capacity to rebel against their own programming, putting them in conflict with other models. In addition, we are seeing some humans beginning to adopt the monotheism of the Cylons, and that this will create conflict within the ranks of the survivors, just as we are beginning to see cracks developing in the solidarity of the Seven.

As Season 4 progresses, I expect to see further recognition on both sides that humans and Cylons must join together for their mutual survival, and that upon reaching earth, they will discover this process already underway; the 12th has begun to create a new race of "hybrid" human/Cylons, which will eventually become terrestrial humanity.

So, Simac is right on that point, at least partially: we ARE cylons, but we are also humans; we are the "next step" in evolution, a human/Cylon merging.

Not even close.

It's Gaeta.