Stats: Necrovalley is a Field Magic (or is that “Spell” now) card.  As we will see later in the Uses/Combinations section, this is for the best.  The only other appropriate forms that it could take would be a Normal or Quick-Play Spell that left an effect residing on the field (too potent and hard to control), or as a Permanent Spell or Trap (making you lose a normal a space in your Spell/Trap Zone).  Yes, it becomes a target for Spell/Trap Removal, but that is the nature of the game.

Effect(s): Two delicious effects.  In simplest terms, the first effect basically means that anything that reaches into the Graveyard from outside the Graveyard or that tries to remove cards from the Graveyard would be negated.  On the other hand, things that take place entirely in the Graveyard-such as the effect of Marie the Fallen One-or things when said card was already in the Graveyard, like Manticore of Darkness, Sinister Serpent, and Vampire Lord, work as normal.  This is a pretty nice effect-a lot of powerful cards are negated.  Things like any “remove X card(s) from your Graveyard to summon”, recursion cards and even Fiber Jar are blocked by its effect. 

Now take a peak at the second effect.  A whole, unique category of Monster, the Gravekeepers, will each gain a +500/+500 stat bonus while this card is active and on the Field.  As the main drawback of said monsters was being a tad under-powered, they go from teeny to titans when on their home turf.

Uses/Combinations: This is the backbone of every serious Gravekeeper deck, and as such most would label Gravekeeper decks a sub category of Necrovalley decks.  Not sure if there is any serious attempts at a deck that doesn’t run at least a few of both together as the main theme: maybe a depletion/removal deck?  Well, outside of this, there is good side-deck material.  In addition to shutting down the oh-so-broken Chaos decks, it makes Necrofear cry and just messes up the normal “drop, revive, and swarm” tactic that most decks at least use as a back up plan.  Some Magic Jammers/Drains can usually be easily found and help protect it.  If you have money or are good at trading, there are some stronger cards too.

If you play at a store using what I believe has been confirmed as the new Japanese ban list (where MST is limited to one-per deck and Harpie's Feather Duster is banned), I think the Necrovalley, as the cornerstone for Gravekeepers, could become quite potent.

Also note that Pharonic Guardian (the set that contained this card), featured multiple cards outside of the Gravekeepers, that got bonuses from it in some way or another, or required it.

Ratings

Casual: 4/5, 4.25/5 with bans.  Gravekeepers are a finely tuned machine with this on the field, and it can screw up a lot of other casual decks.  In fact, it’s almost too much for casual.

Tournament: 3.75/5, 4/5 with bans.  Alas, the Gravekeeper decks are just a hair to weak to be dominant here.  Still, Necrovalley itself is great to counter Chaos, and may very well fit into most side-decks.

Limited: 4/5-Dude, set revolves around the Gravekeepers.  It will probably be a shock to not pull at least a handful of related cards to it.

Summary

Great card that just needs those new bans to get a chance to shine… and maybe some Gravekeeper/Necrovalley specific S/T destruction. ;)