My own hypothesis on the nature of Primals [SPOILERS]

[Anonymoose]

Correct me if im wrong but when the keeper of the lake destroyed the garlean airship didnt he realease primals (ifrit, titan ect)

Dunno. That's sure what it looked like, though, didn't it? All we know for sure is that Mor Dhona is where the aetherial rivers converge, and that Midgardsormr guarded a seal on that aether, and when he died, we saw a whole bunch of primals flying out of it. We've never been told what that was. It looked like primals were sealed there, but then what sealed them? The Allag? Why there? In what? We can speculate, but we have no confirmation. For all we know, it was a visual representation of "Oh, hey, lots of aether, and now primals can be summoned." On the other hand, Odin was sealed in a crystal in a spring. Maybe the other primals were sealed in the most crystalline region of the realm beneath a giant lake. Maybe we'll find out in 2.5!

[appledoze]

I agree with anonymoose. It's likely a representation of the releasing of the aether seal under Silvertear. Although as I see it, its possible that even after a primal's physical form is destroyed, their aetheric essence still exists in the flow of aether after they are first summoned. The breaking of the seal in the lake meant that it became feasible to summon primals since large amounts of aether are required to do so.

As for Odin, I feel that his case is that of a person who either became a vessel like Iceheart, or became a primal himself like Louisoix. However he was somehow sealed away by Urth instead of being defeated. Its likely the breaking of the seal in the lake allowed him to gain enough strength to break free.

[Eggnook24]

Pffft, what a stupid theory.

Everyone knows you can't summon Santa, he only shows up on the Eve of Christmas every year.

...WAIT! Mall Santas! They must have come from the Aether! I understand now. Thank you.

[treuhavik]

Odin was released when the Garleans began digging around, afaik.

I like to picture the Garleans backing up their backhoe, bumping into a giant glamour dispeller wedged a wall, cracking it and releasing his spirit. Odin then roflstops the digging crew and walks away in slow-motion.