Umbra's Ebony armor can be found in the elven ruin of Vindasel. Vindasel is southwest of the Imperial City. It is east along the road from the Clavicus Vile's Shrine, and west of Pell's Gate and the Old Bridge. The armor can be found on a Bosmer called Umbra inside. Killing her is linked to the Clavicus Vile Daedra quest at the Shrine of Clavicus Vile. Umbra is one of the hardest enemies in the game but her armor is very good and looks almost like ebony armor, the only exeption is the helmet. At any level below 15, Umbra's Armor is powerful in it own right, but is inferior in terms of Armor Value to regular Ebony armor. The added weight means its better to replace Umbras armor as soon as regular ebony armor appears. Above level 15, It gives the same weight and armor rating as regular armor. ( added note armour does not increase unless your heavy armour skill does technically unless you train your heavy armour skill it will never increase so as your actual level could increase due to destruction magic or conjuration etc... you may not alter the defence of the heavy armour).