Ok so i played skyrim and i just want to knpw why people are calling alduin akatosh. How could akatosh want to destroy the world after saving it?

Alduin is Akatosh's first child I think, I remember Alduin saying something like that.

But why would akatosh let alduin destroy the world?

Akatosh isn't really allowed to do much of anything. None of the Aedra are.

The reason people think Alduin is Akatosh is because there's a book (somebody tried claiming more) that makes the claim in-game. But it's essentially just the speculation of scholars of the setting, not objective fact.

Maybe he knew, or trusted Dragonborn to save it?

Seams odd how the aedra created the world yet they cannot alter it in any way.. Any idea what there purpose is?

As far as I know...

The Aedra (the divines as you know them) can merely influence the world, not directly effect the world like the Daedra can because they got a bad deal in making the world where people live. Even the Daedra can't directly effect the world until they are called into it (like in the Oblivion crisis). I doubt that Akatosh wants the world destroyed, its just that even if he told Alduin to stop, he really couldn't enforce his will.

Because the Aedra aren't allowed to intervene directly, only Daedra can do that.

He wouldn't, that's why you were given the Blessing of Akatosh, and became Dovahkiin.

Daedra don't need to be summond into the world, they can do it on there own, it's the dragon fires that protect Tamriel from Oblivion, not the Daedric princes.

They can do it on their own once they're over here, but someone has to get them over here in the first place. The dragon fires and whatever protects the world now, protects the world from the daedra as well as the daedric princess (which are just the strongest of the daedra anyways). Even when the dragon fires went out, cultists had to open oblivion gates, they didn't just pop up.

So if the dragon fires are out then there is nothing stopping the daedric lords from entering nirn and directly stopping alduin cuase im certant they dont want all of there followers from dieing

I think it was explained that when Martin offed himself by evolving into charrizard, that a new barrier of some type was put up that does the same thing only without the need of the dragon fires.

Ahhha charzard