Considering that the alignment, which is clearly some kind of prophesied extinction level event unless side of "light" wins it, i'd say that having good working relationship with the largest and most powerful, even if bit fractured at the moment, nation is good idea.
Nitpick from my part mostly, it isn't "prophesied" as is, it is "natural" event that happens every 1000 or so years. Natural in quotes because the origin isn't anything natural, but stems to the whole war between ancients and the gods. Which kind of ended up fucking the world, the stars, the weave of fates, and magic up for a really long time. And the alignment is the result of the magics that were used by both sides to rip the barriers between life and death apart.
Then the first "war of souls" started because bunch of power hungry necromancer and demon worshippers noticed that "hey, there are tons of souls hiding in the afterlife and with the barriers almost gone they are easy to pull and consume for power!" and thus they started doing that and killing and eating a bunch of people (mostly demons since they get hungry). And then the still living beings decided that "fuck this" and fought back. And the cycle tends to repeat itself because there is always some jackass wanting to become the next Emperor/King/Caliph/Sultan/Maharadza or just wants to rule the world because reasons.
... I might have oversimplified the thing a lot, but that's the basic idea of the thing. There is some stuff about it later from the characters perspective, which might not be entirely accurate, but close enough.
If I remember correctly, it was stated that whoever occupied the tower was the highest ranking as it had been empty for a long time. Or at least not fully controlled. It was said a lot of others had attempted to take and own the tower, but they all failed.
The mage college in the Empire sent the MC out to fail. Just like all the others before him did. Which means that there is something about the MC that they fear or dislike or both.
Of the Northern mages. At least that was the intention, need to check do I need to clarify that. But the line of thought people in power was that "it doesn't hurt to try to send someone who actually knows how to fight up north and maybe, just maybe be the unifying factor for the Northen mages when the time comes."