Definitely Krs-one, he tore up marley marl, mc shan, roxhanne shante, and he's still making diss records just at even faker bitches.
Next battle, Nas verses Tupac, ok I have a lot of respect for tupac, but tupac just has those disses without any wit like "that's why I fucked your girl you fat motherfucker", If nas had pulled an Ether on Tupac, he would have shut pac up