The Rejoining (Spoilers for EVERYTHING up to 2.55, welcome to Lore)

[Enkidoh]

So what does Midgardsomr have to do with all of this? Didn't he remove Hydaelyn's blessing from the WoL so they could be free and choose for themselves?

1. How can he resurrect?
2. How can he remove Hydaelyn's blessing?
3. Why did he remove Hydaelyn's blessing?

Well, I'm still not entirely convinced he actually did do it for that reason, and has for more malevolent goals for us (I mean, look at him, every time he's spoken it's to belittle, taunt and put down the player - the last scene of 2.55 has him smirking as we stand at the Gates of Judgement and tells us in no uncertain terms that Ishgard will not bring sanctuary to us but just "Delusion, despair and death." After all, he only removed the Blessing of Light from us because it stopped him killing us outright which is what he tried to at first, and which his massive ego wouldn't allow.

As for how he managed to strip the Blessing, other than the most common line of reasoning is that he actually did it under Hydaelyn's orders as a sort of perverse test of our resolve (which I don't buy - the fact it materialized to stop him attacking us kind of throws that idea out the window), I think the most likely option is because the Crystals were taken from defeated enemies (including the Primals), he probably could therefore manipulate it in any way he chose, which is exactly what he's done.

And given the fact that Nabrielies just happened to show up at the Rising Stones not long after this happens smugly declaring "the Light no longer protects this place," I suspect Midgard's stripping of the Blessing of Light was all a manipulation by the Ascians, which even Midgard probably isn't aware of. But I guess we'll find out.

I'm also wondering why the Ascians want the beastmen and etc. to summon primals -- how does that fit into their goal? The Scions and company seem to think that sapping the aether from Hydaelyn kills the planet, so what does that have to do with resurrecting Zodiark?

Lahabrea explained the reason for this back during his big 'the reason you suck' speech in the Praetorium after destroying the Ultima Weapon - to cause Zodairk's rebirth requires an enormous amount of 'chaotic energy' (as he terms it), which the summoning of the Primals increases.

He doesn't go into detail exactly how this works, only that the existence of the Primals is essential to it, and that the Scions and the Warrior of Light were stubborn thorns in his side as a result (due to, you know, always killing the Primals whenever they're summoned). Either way, the mechanics of exactly how Primal summoning fits into the Ascians Zodiark revival plan will most likely be revealed as the story progresses.