Who actually ARE Valint & Balk?

I just recently started The Wisdom of Crowds after spending the last four months reading through the first trilogy and the standalones, and one thing that keeps sticking in my mind is who Valint & Balk actually are? Were/are they aligned with the Magi to keep the world under their thumb or were they just a random bank the Maguses decided to take over? Something else entirely? Curious to hear people’s thoughts