I'm running your basic run-of-the-mill dragon deck (Ya know, Dany and the 3 dragons, all QoD of course) and their various supports and heavily using ambush and running Heir to the Iron Throne. For awhile I've been dominating my circle of friends in melee until one day, my one rival unleashed his Asshai Shadows deck, and it DESTROYED ME! He basically used a combination of Wicked Seductress (RoR), Margaery Tyrell (TftRK), the Black Cells (TftRK) and Sister of Truth (KotStorm) to infintely trigger them to kneel and/or blank all my dragons. Not only is this happening to me constantly, but I also have to deal with two other players trying to destroy me. Basically I'm looking for good anti-shadow cards to put in my deck. All I've got so far is The King's Law plot card.

There isn't really a silver bullet to Shadows cards, but it sounds like the problem is your deck is too aggressive. If you're the highest threat out there in a melee, chances are good that anyone using control effects will try to shut you down. Dragon decks are actually pretty easy to control (one of the reasons they don't do so well in joust) since you are focused on getting a few specific guys out there and then getting the win before they can be killed, discarded etc. You best option may be to try making a deal with him instead of being aggressive, or making a deal with another player who can control his control effects.