[novalysis]

Negi an idiot? HERESY!

As for the other question: Short answer, he's the MC. Slightly longer answer-

Spoiler for Not yet revealed:

He's part of the clearers - you see, there's the concept of "front-line" not yet touched upon in the anime, but Kirito spents alot of his time at the very front of the fighting towards the 100th floor- those like him are called clearers. Asuna is another.