When I look at the trailer again, it seems like dragons will be enemies in a very noticeable way. What I don't understand why it is said that no one would believe that they existed? And what defeat is being talked about?
Do you think that dragons here are just a symbol for Alduin? I thought about that, but it doesn't fit with "their" language is the dragon language, pretty much proves the above but I don't understand it.

Akatosh again oh well you can't have Elder Scrolls without the nine Divines. Maybe when Martin became the Avatar of Akatosh it did something to the bind that held the world together or the appearance of Akatosh in Oblivion caused the other Dragons to awaken. Who knows but Akatosh will have another predominate role in the game. The Mag article hopefully will clear some things up until E3

Well Alduin is considered the "World Eater" by the Nords, a title that "comes from myths that depict him as the horrible, rauaging firestorm that destroyed the last world to begin this one".

So I expect that Alduin is more of a force, dragons fit the firestorm mentioned, unleashed by the Nordic pantheon to destroy/purge the world to begin anew.

And the Dragonborn would be someone chosen, sent, or created by Akatosh and the Nine Divines. I think the Dragonborn is chosen like Saint Alessia was. But this is only plausible if the Nordic pantheon and the Eight divines are not the same beings viewed differently. Unless there is infighting amongst the Gods...?

Read Cipher 8s thread on the subject. He predicted Akatosh would be the main antagonist before the cover was revealed, and explained his theory thoroughly.

So if Akatosh is the possible main antagonist then how the hell is that going to affect the other 8 divines and the 16 Daedric Lords. My guess is that Martins actions when he became the avatar caused something to happen.

...again; read Cipher 8's thread. It's all there.

I read it and it makes a lot of sense. I still can't believe that Akatosh is going to be the main Antagonist.

Kinda makes ya think twice about helping out Martin in Oblivion now, eh? Wouldn't it be funny if the actions of the Champion of Cyrodiil paved the way for Akatosh's bad side to wake up again, similar to the way the Nerevarine's assault on Lorkhan's Heart helped lower the barriers holding back oblivion?

I don't think it's actually a "bad side" of Akatosh we're talking about; he is a God, afterall. I doubt he has any morality that we mortals can appreciate: he does what needs to be done. The Nords view him as bad, and the Imperials as good, but that's a subjective thing, and it doesn't mean we're actually talking about a split personality. If he currently, for some reason, needs to destroy this world and begin anew, that is what he will do.

Remember guys, the religion of the 9 is not worshiped by all. In fact, it is nothing more than a diluted merrish religion, with bits of nordic religion in it that Alessia created, as she wanted to keep the merithic pantheon, but also to not piss off the nords that helped her revolt. What Alessia pretty much did was take the merithic gods, and made them good, benevolent, etc, and toned down Shor (Lorkhan) into Shezarr and made him the god of human achievement, as opposed to a blood thirsty, highly anti-mer and very pro-human god, or a malevolent trickster who created Mundus (the universe) to take away everyone's awesome godness. Akatosh, like with the mer, sits as the head of the gods. Shezarr, however, was forgotten and Talos took over as his replacement though mantling.

With the nords, they hold that Alduin (Akatosh) is a world consuming dragon, bringing the end of the previous kalpa, causing a new one to arise. To the nords, he is not a welcomed deity. Shor (Lorkhan), is a very pro-human, who fights the foreign gods (the merish pantheon), sits as the head god of the nordic pantheon, and created Mundus as a form of divine mercy designed to empower mortals, who were lesser spirits in the Dawn Era (something Vivec believes too, Mundus as Shor's divine mercy).

With the mer, Auri-El (Akatosh) is a benevolent god, who fights against Lorkhan, as Lorkhan tricked the aedra into self-mutilation, and weakened them along with all who are now mortals. For this, Lorkhan had his heart ripped out by Trinimac, Auri-El's champion, and shot the heart with his bow to what is now Red Mountain.

And that's pretty much the short of the three pantheons. Just remember, Akatosh is probably not going to be your friend, as he is also Alduin, and he is very hungry.