Garthanos
Arcadian Knight
Really though did 5e even provide for anything like that origin? They are fine with superhero class casters without any required a badass origin.Right, but then their origin makes them non-mundane, not their class.
Oh and Deva or whatever the new variant is call by any other name could smell as sweet (but he still is no high level D&D type)gandalf's race/species was a maiar.
Of course he is a mentor archetype not the hero role sheesh, we were talking potency of casters in myth and legend not being so over grand.