FFTA - Hume - Black Mage

Nu Mou are better suited to be raised as Black Mages because their magic power growth is better than that of Moogles and Humans. Black Mages can be one of the most powerful classes early on if raised right and have the right equipment. A combination you should try is equipping a Black Robe and having the Support Ability Turbo MP from the White Mage class, or you could use the Magic Pow+ Support Ability from the Alchemist class. An important thing to remember is what elemental rod the Black Mage will be using, as the correct rod will enhance the power of the spell (e.g. The Flame Rod enhances Firaga).