Normal
I think what he means by twice is you have to have beat crota on hard at least once before the drop is available, I have done it on my hunter multiple times each weeks since hard came out to test the theory if it can be dropped on a non reward run. I belive it is just as rare a drop as the vex just do your hard runs each week and you will get it. Three people i raid with have already had it drop KoG Runner, Bwownie and XGC Bryan XS.