Nagi Springfield

Negi's father and a legendary wizard. The origin of his title is ambiguous; some bill him as the master of a thousand spells (which is patently untrue since he admits to being a dropout who only knows a handful of spells (and needs to read out of pocket notes to cast other spells), however, this was stated in a dream that Evangeline had, and because she "hates" him, may not be true, but it seems to have been verified by Asuna having Nagi say something to the same effect during her most detailed flashback dream) and there is also a rumor that he made probationary contracts with a thousand different girls (though this is almost certainly just a lie of Albert Chamomile's, meant to inspire Negi to make many contracts and earn Chamo-kun a huge brokerage fee with the Ermine Society). Nagi is so strong, in both magical and physical combat, that he does not even need any Ministra Magi to help him. His fighting style was that of a magic swordsman, using both speedy magic casting and hand-to-hand combat in tandem.

Source: Wikipedia