Magely ones, more likely than not. Intelligence based, philosophical people. But if you're looking for a set of skills to make a character with, then real people don't conform to stock skill sets like that. I mean, I once met a girl who was a receptionist but wanted to be a mechanic. I was baffled. Maybe she was multi-classing.
I approached it from the perspective of "What classes do they teach at Crystal Like Law tower?"
Mysticism, (We have examples of it in "last year")
Alteration (Again, in "Last year")
Conjuration (they have one of the few means of reaching oblivion from Mundus on their campus---- heavily guarded of course.)
Others would be required to help with mental fortitude:
Illusion-- One needs to understand this, to prevent from being manipulated.
Speech craft-- Must be well-spoken in order to engage in high courts.
Mercantile-- Similar to above.
There would also likely be some light combat training for advanced members, even though Psiiijjj seem to be mostly passive aggressive.