It will be fully elaborated on in the OOC. To summarise:

Firstly, there are the First Children and the Second Children. The Second Children are humans; the First Children are a race known as the ithuri. The ithuri rival humans in power and populace, but unlike humans are united by the Imyassi Empire. The First Children once ruled the world, then the Second Children came (and inherited magic and, as the tale goes, the favour of the gods) and started pushing the ithuri into the heart of the world. Humanity brought a great race and empire to its knees, killed their God Emperor and for the next millenniums the ithuri were forced to fight to re-establish a place for themselves (rising once again as the Imyassi Empire). Hatred is an understatement for what most ithuri feel regarding humanity. Sethael is an ithuri.

Secondly, the centre of all arcane power resides in At'aine, the Well of the World, a gift to the First and Second Children. The Well has ancestrally been neutral ground, guarded by the first maegi of the Conclave, until the Conclave ceded the Well to the human nation of Maltheria. Naturally, the ithuri took great offence to this, and thus for centuries after, the ithuri of the northern empire have warred against the northern kingdoms for control of the Well. As you'd guess, there have been seven such wars, though the seventh was bigger and bloodier than usual.