It was said, mostly by Hacka, that he fought alongside Azhag, and was the one who first proclaimed him 'the Slaughterer'. He also mentioned single-handedly killing Sigmar and being a drinking buddy of Gork (or possibly Mork). Whatever the truth, Hacka acquired this slender and rather Elven looking sword from somewhere strange and nobody ever felt much like asking where. Not after the last time, anyway.