The first were the kin of the World Tree itself; the spirits of the three planes and the creatures they made as their children. The others were wandering spirits from beyond the stars brought there for reasons of their own. The spirit of the central plane, Ingia, welcomed these wandering spirits and together they formed the realm that would go on to bear her name.
At first there were three kinds of creatures; elementals, nymphs, and animals. The gods granted their blessings onto the beasts they made and were content with the world that resulted. When birds flaunted and danced, they were praying to Colidyr. When puffer fish dug intricate patterns in the sand or bowerbrids gathered bright colored objects to decorate their home they honored Hala. When they build tools and strategy they give praise to Sanji. For a time, this was all. Creatures lived and died and the divine watched over it all with fondness. However, one day a group of nymphs sought them out and told of some creatures, once blessed by Sanji, had begun to change. Their intelligence was beginning to push beyond what had been given. The gods were curios about these animals and decided to experiment; picking whichever ones caught their fancy and giving them even more blessings. From their they only began to grow faster, becoming most of the humanoid races we now know today. The rest came when nymphs saw these new creatures and grew curios about what the world was becoming and took new mortal forms to be able to truly be a part of this new world.
Many thousands of years after the beginning of humanoid creatures the world of Ingia can be largely split into two regions.
The first is The Continent of Arbor, or the Arborland, home of the World Tree. The fabric between worlds is thin here so otherworldly influence is commonplace. Children being born with strange arcane powers, fey can be found wandering the land and the presence of the gods is most strongly felt here. These nations focus on magic for the advancement of their people.
The second is The Continent of Stone, or the Stoneland, where the people lack the intimate relationship with the extended realms that those on the Arborland have. To keep pace they focused development on technology. The Stoneland has developed everything from guns to rudimentary vehicles and even Warforged. The magic that is used is in the realm of magic study, artificers and wizards, rarely bards or druids. The only major exception to this is the Znir gnolls. Having been created in one of very few times that an otherworldly creature made its way to the Stoneland, the Znir Gnolls are a notable fragment of planar magic in a literal and metaphorical desert. As such, you can find what are known as Bloodkeepers in their midst; spell casters that mimic a warlock but instead of directly bargaining with a fiend they instead pull that magic from their inherent connection to the creatures.