Mordor, the evil forces of Sauron relying upon weight of orcs and disposable troops to get quick control of the battlefield until the shock troops arrive - the trolls. Mordor is vulnerable at the start to raids on it's economy slowing it's progression to the late game where it is dominant with orc archer combos, trolls and mass leadership in the form of the Witch King, drummer trolls and Darkness. Throw in a few variations involving haradrim, catapults or the massive mumakil and you have one of the most potent forces in the game to deal with. What you need... is a guide.
General Guides:Mordor Hero Guide
Mordor Unit Guide
Mordor Vs. FoL - Starting Pathways On All QM Maps
Master Guides:Mordor vs. Rohan
Mordor vs. Gondor
Mordor vs Isengard
Mordor vs. Mordor
Quick Match Guides:Dunharrow
Eastern Rohan
West Emnet
Mordor vs Forces of Light on Rohan