Find an Iron Limbcleaver in Grimrail Depot. Part of this quest happens in Lunarfall, Grimrail Depot, Frostwall, Gorgrond and Ashran.
Upon completion of this quest you will gain 1 350 experience and will receive Gamon's Braid to.
Here you can buy Cleaving Time Boost for EU or US Servers.
You'll get guide for completing Cleaving Time Boost