Can someone explain Dalamud and Project Meteor and Meteor spell?

[Hainiryun]

1. Faith yes, Crystals not necesarily. Primals need Aether to sustain their physical forms. Crystals are just convenient concentrations of the stuff. Without Crystals Primals can and will leech ambient aether from the world at large, it's one of the reasons even non hostile Primals can't be allowed to manifest for too long.

2. The sealing spell hasn't been detailed too much as far as I know, but it was heavily reliant on faith to channel the power/perceived power of the Twelve. Dalmund being the manifestation of this sort of fits. Dalmund was what kept Bahamut sealed so Dalmund is something you could concieve being able to hold him.

3. Not directly, House Darnus held surviving Allagan records about Dalmund which conveniently omitted any mention of the Primal itself. The original aim was just to use the energy stored within Dalmund for various purposes. That failed and the project was shelved, Nael brought it back up when Solus decided he wanted to wipe out the Primal threat in Eorzea for good and break the stalemate that had developed after the battle of Silvertear Skies.

4. Garlean command thought it was just a big orb full of energy, they were essentially just planning to drop a big bomb. Nael knew what she was doing by the end, having already been tempered by Bahamut via the Lunar Transmitter.

5. Meteor is a legacy spell name really. It's the ultimate black magic in many entries so it makes sense to use it as the ultimate Black Mage spell. It's distinct from Project Meteor though, which is a more literal "drop a giant doom rock on their heads" scenario.

6. Again, Project Meteor is distinct from the spell Meteor. Nael wasn't using a spell, Project Meteor used an Allagan Lunar Transmitter to call down the Dalmund satelite.