This is actually helpful wrote:

The quest says the north tower is in "Blademaul Hold". This is easy to confuse with "Bladespire Hold", especially since the actual name of the place is "Bloodmaul Outpost" and not "Blademaul Hold".

The north tower is to the south, in Bloodmaul Outpost. The quest is easy to do, as long as Blizzard learns what the names are that they have given everything. Wasted about thirty minutes trying to place the banner in every freaking tower inside the wrong damn base.