The best part about this deck is it's amazing search power and the synergy of effects with each other, with Gravekeeper's Recruiter as your main search engine. Baggy Sleeves is great because it further increases your card advantage whenever a high leveled monster you control is destroyed.
Note: :To see the latest update of Gravekeeper Decklist, please click the link below:
When Gravekeeper's Recruiter is sent from field to graveyard, you can search any Gravekeeper monster from your deck and add it to hand. This effect is really good as Gravekeeper's Recruiter only needs to be sent to the graveyard not destroyed meaning you can use him as tribute to get his effect out.
You can choose which effect to use when you tribute summon Gravekeeper's Oracle using Gravekeeper monsters. It's almost always safer to lower your opponent's attack and defense since it weakens them and makes your other monsters able to take them down without the threat of a Mirror Wall, but destroying their set monsters can be good too to prevent flip effects if you are certain you can take down their face-up monsters. Increasing his attack can be useful when you tribute 2 or more gravekeeper monsters.
Gravekeeper's Visionary is a good tech card to put in the deck. Summon him when you have a Gravekeeper monster in your hand, so that you can protect it from getting destroyed. Having more Gravekeeper monster in the grave will make Visionary stronger.
This deck has plenty of potential to go against every other deck(EXCEPT FUR HIRE??!!) and its capabilities are great, but the fact remains that all rogue decks require more skill and research to play against Konami's choice of meta game(which usually is OP for rich players). However, if you truly understand the core of the deck, you might develop the skill to KOG here.
Put it on a character skill so that players are forced to use the skill instead of being able to combo it with other decks easily. You could make the skill "if you have a gravekeeper monster on the field, activate one necrovalley from outside your deck. If the monster is face down, reveal it to your opponent, and then return it to its original posititon. This can be used only once per duel."