Always seemed a pretty easy answer to me I guess.

Die-> Judged by Kelemvor-> Go to what ever spiritual destination your faith says waits for you, The wall for Aethists, or who ever owns your soul legaly.

...Going back even further, we have the nether scrolls, that seem to have been stolen from dragon's magic and are the basis of all modern common magic...

According to the oldest myths, Lord Ao created the universe that now holds the world of Toril. Through this act of creation, protoplasmic raw existence took the form of twin deities, one representing light and one representing darkness. These deities, Selûne and Shar, birthed the heavly bodies, in the process creating Chauntea as the animating spirit of the world of Toril. Chauntea begged the sisters to grant her world warmth and light that life might flourish upon it. Selûne relented, igniting the sun with elemental fire. Shar, who treasured the primordial darkness and resented Chauntea's concept of life, lashed out at her sister, initiatng a conflict that has endured to the present day. Enraged, the Lady of Loss snuffed out the lights of Selûne, greatly weakening her in magical battle. Finally, the Moonmaiden tore a piece of her magical essence from herself and flung it at Shar. When the blast hit the Dark Deity, it ripped away some of her essence as well. From the meld of light and dark, energies came Mystryl, a being of pure magic who went on to shepard the Weave blanketing Toril.

Chauntea is one of the oldest Faerûnian deities. Shar and Selûne predate her, having given her life when they created the world of Toril. In the ensuing millennia, Chauntea has forged passionate relationships with several deities, many of whom no longer exist in any meaningful form. So too has she battled (and even destroyed) deities who schemed to befoul Chauntea's world. Some of her worshipers claim that Chauntea is the progenitor of all the mortal races, that the creatures who populate the world first emerged from her womb in the days when the air was quiet and the earth was still.

Shar secretly created the Shadow Weave long ago in response to Selûne's creation of Mystryl and the Weave (to which Shar inadvertently contributed.)

The birth of the being known as Mystryl did more than just balance the war between the sisters of light and darkness. Her very existence changed the reality of the universe by creating the Weave, the conduit that allows creatures to use magic. Suddenly, rather than magic being restricted to deties, any creature with the talent or training could draw upon the power of magic through the Weave. When sentient creatures appeared on Toril, some of them learned to use the Weave while shamans and clerics drew their magic directly from the deities. Acknowledgment of her gift led to worship, and Mystryl drew power from that, becoming one of the more powerful deities.

The Weave acts as both a barrier and a gate between raw magic and the world. With the Weave in place, mortals can access magic and are protected from the harmful effects of contacting raw magic while still able to rap its refined energy. With the Weave gone, raw magic quickly dissipates from the world, but only after disrupting existing magic and lashing out at nearby magical conductors.

Not entirely accurate from a few standpoints. First, it's unknown who created the Nether Scrolls, which indeed were the cause for the nethenese research on magic to really take off. The Scrolls are thought to have been passed down by the Creator Races, found in Realmspace or were a gift from Mystryl herself.

Secondly it's stated that some races, such as the elves, already had their own type of magic since before the discovery of the Scrolls. It's known that in its early days, the Nethenese empire traded with the nearby elven kingdoms and one of the things they "imported" were spells and knowledge of magic.

So, at least from this angle, I think your argument is flawed, soundofastream.

For all we know, Io might be the equivalent of Ao, but for dragons (or just another aspect of Ao).

Yes, but the dragons have been around (and the dragon gods) longer than most of those deities. Thus Io, could arguably, be the creator of magic. That's the problem, sourcebooks contradict themselves over and over and are largely silent when it comes to the demi-human or non-human gods. Human gods, get the limelight, but it doesn't mean they're right.

For all we know, Io might be the equivalent of Ao, but for dragons (or just another aspect of Ao). Its largely silent on how the creator race gods, came about and whether or not, they surpass or are older than Realmspace.

In he wake of the Days of Thunder, dragons rose to rule Faerun. Elven myth, recorded in the form of the Parwiccan Cycle, speaks of the Tearfall, thought to refer to a rain of meteors that fell from the sky. Some scholars interpret the ancient texts as suggesting the meteors precipitated a dramatic climatic change, which in turn sparked the rapid evolution of proto-dragons (little more than large lizards) into the varied forms of dragonkind known today. Others claim that the meteors were in fact falling dragon eggs, from which the varied races of dragonkind were born into this world.

In the sourcebook that deals with ancient civilisations, its states that dragonic magic was thought to have been written down by dragons, stolen by the lesser races, during the first draconic wars with the lesser races, in the form of the nether scrolls...there's also a story about it, in that FR novel series dealing with Elves, which shows elves stealing the magic from a gold dragon, which, kick starts off the creator race wars as the lesser races free themselves from their draconic masters.

Here it states that dragons didn't exist until they were spontaneously created after the Days of Thunder. Regardless of which particular interpretation you view, the dragons were born here and didn't exist in a void somehow before Chauntea (who was the land of Faerun)...

All references to Io or "Asgorath" creating the world and all other deities are always mentioned with the caveat that 'this is what is believed by Dragons'. Whereas every reference to the creation of the world state Lord Ao begat Shar and Selune, who begat Chauntea and Mystryl, and so on, without any mention of 'this is what is believed by non-dragons'. It's as dry as a feat or spell description.

Chauntea is Toril.