Ages ago humans leave Kobol. The ones we know create the 12 colonies and build toaster cylons which rebel and stop fighting colonials around 40 years ago as shown in young Adama’s flashbacks in Razor.

The 13th tribe of humans built their own cylons, but more advanced, aging, human-like with reproductive and downloadable capabilities which somehow take over Earth.

Somehow 2,000 years ago Earth gets nuked and only 5 special cylons escape and go search for the colonials leaving clues through the galaxy (the temple of 5, maybe earth’s location in kobol, etc). They find their cylon brothers 40 years ago and tell them to stop fighting the colonials and they build 7 models of cylon-humans (skin jobs) with programming not to seek the final 5 while they go live among the colonials.

Finally the new cylons nuke the colonies fulfilling “everything has happened before” and about Kara being the harbinger of death still remains to be seen.

I agree that Dee is just dead and that Six is copied from Ellen but still Ellen is an aging cylon and Six is not although at the intro of the episode this should be confirmed.

Baltar is a “special” human as well as Kara, Laura, etc (people with visions, telepathic connections stuff like that). And there are human and hybrid oracles which predict the future. This is the theme of the show.

Two thousand years ago, Earth was advanced enough to send colonists into space. These colonists founded the 12 colonies. Back on Earth, technology had progressed to the point where humans who died could have their consciousnesses translated digitally into artificial bodies, sort of a more advanced version of cryogenics people who have themselves frozen at death. There was some kind of ongoing war on Earth. Soldiers for the warring parties used this technology to keep fighting, which gets you Cylon bodies in war armor, which look like Centurions. Finally, the war on Earth went nuclear, killing everyone. For some reason, only five Earthlings managed to get downloaded to new bodies. These five go off in search of the colonials. The only way for just five people to make the trip was with the assistance of an artificial intelligence, which made the other seven, newer model Cylons. How the final five got integrated with the humans and the seven ended up somewhere else with their mythology is not too difficult to explain from this starting point.

I’m also on board with the Ellen/Six theory. Aging could be the theme to Ellen and Saul Tigh’s relationship. It doesn’t exclude the idea that older models of Cylons took some humans and copied their DNA to give themselves skins.

And I think Kara probably will kill all present humans in the show. (The writers seem to take joy in destroying everyone.) “Life” would go on in the form of skinjobs. Six and Tigh’s ability to have kids lessen the difference between humans and Cylons now, anyway. Cylons can’t resurrect anymore. And if you don’t tell those Cylon kids they’re Cylon, how else would they know they weren’t human?

I always thought that they’d find Earth post-apocalyptic, although I wasn’t sure whether it’d be in a time-frame close to our own or in the distant past/future and I didn’t think it’d be colonized by Cylons. But with Starbuck subplot, I am leaning towards the super-advanced race of Cylons and/or humans/”gods” manipulating events with the intent to either assure the cycle continues and civilization survives or end the cycle. Anyone familiar with the original show will remember the extremely advanced humans with seemingly mystical powers in the bright white ships who secretly assisted the Colonials on their way. They were thought of as “angels” of a sort, but were just evolved humans. A version of them could be behind events in the new BSG. I don’t think we’ll be seeing Edward James Olmos moving coins with his mind like we did Lorne Green , but who knows? This would make more sense than the half-assed time travel/spatial anomaly Star Trek-thing that BSG has tried to avoid.

As for Kira’s viper? Who know
The 5th – Pretty sure it’s Ellen
Dee- Wow, that was a powerful moment.