Who is the highest ranking light magic user as in healing magic

The two classes that effectively use light magic are paladins and holy priests. Priests are the best known healing class, and are one of the most in-demand classes in terms of healing, since they are built to BE the healers. Paladins can heal as well (with the right talent tree), and could technically step in as a tank in a pinch, but priests are still the best healers in the game.