The lesser races of orcs were driven unwillingly to the Master's wars. Uruks and Trolls rounded up stragglers and herd them from Nurn to Udun. The mannish lands around Mordor were stirred into a frenzy by the build-up of troops and materials of war.
This little used card can pack a punch. Three separate attacks, 12 strikes before enhancers, it's enough to put a wrinkle in the plans of even a Elf Lord, much less a couple of hobbits trying to make a deposit. The main limiting factor for the attacks is that a company has to move through Nurn. However, now that all companies moving to Mount Doom must either stop in Imlad Morgul, play Ash Mountain or Mountain of Shadows, or pass through Nurn, there is a real chance to use this card against hero One Ring decks. Even if you play it early, it's permanent after all, it can convince a Ring company to stop in Imlad Morgul - so you can plan your 'welcoming committee' accordingly.
But wait, what's this fine print at the bottom? A full -6 is given to influencing faction in seven different regions around Mordor. And Muster can not be used. If your opponent is a hero, then we are looking at: Easterings (4 MP), Southrons (5 MP), Variags of Khand (4 MP), Haradrim (4 MP), Nurniags (5 MP), and the Wain-easterlings (3 MP). In short, just about every high point hero faction in Middle-Earth.
This card has no effect on minion players. However, minion players can still play this card - with full effect - against hero opponents. For example, Ren the Ringwraith can hop a Black Horse and recruit the Southrons. Then when it looks like Gandalf has delusions of converting the Southrons to the side of good (a 7 MP swing) Ren calls for Mordor in Arms. Suddenly Gandalf is stuck deep within enemy territory with only a slim chance of getting what he came for. Evil laughter is required at this point.
The main drawbacks of this card are its limited area of effect and its vulnerability to Marvels Told. If your opponent is running a Rivendale based deck and never intends to go near Mordor, then this card would just be taking up space. On the other hand, if she does want to go there, you can expect Marvels Told to be used. Also, it is completely useless against minions opponents.
A good strategy for Mordor in Arms is to play it only when your enemy shows an interest in the area. If it is late in the deck, perhaps you have already managed to flush out any Marvel's Told or at least, he will have fewer turns to respond to this new threat. Therefore, Mordor in Arms should almost always be a sideboard card.
You only move it into your deck once your opponents intentions are known. I can not think of a single sideboard that wouldn't benefit from it, unless you are playing strictly minion opponents. There are other hazard permanents that are - and always will be - more popular than Mordor in Arms. It's hard to argue with the brute force of The Will of Sauron or the subtle malice of Eyes of the Shadow. But especially for minions, it's nice to be backed up by the forces of Mordor.
Original card review taken from : http://fan.theonering.net/morgulrats/
With the authorization of the webmaster.
The reviewing team consisted of Gwaihir (Chris Farrell), Gimli (Nathan Bruinooge), Ohtar (Charles E. Bouldin, Esq.), Radagast (James Kight), Joshua B. Grace (Beorn), Martijn Steultjens (Fram Frumgarson), Jason Klank (Saruman) and Jeffery Dobberpuhl (Wormtongue)