Talk:Wit's End/@comment-2250198-20140324164805/@comment-24395984-20140804004659

Even with abyssal scepter this would not reduce the targets MR below 0 as percent magic reduction is applied after flat magic reduction if you look at the example here:

http://leagueoflegends.wikia.com/wiki/Magic_penetration

Take note the difference between penetration and reduction. Stacks of Amumu's passive combined with stacks of Wit's End will put the target below 0 MR. (NOTE: I got all the information from this from this wiki, no actual game tests)