I'm curious how well Storm Cauldron would work with Lavinia. On one hand, it makes it easier for your opponents to cast spells, as they'll have more lands fielded. My gut says this card will not be worth a slot, but it still might be worth playtesting.

I would consider adding Teferi, Mage of Zhalfir. Besides being a generally nifty card, he provides a second lock alongside Knowledge Pool and Omen Machine.

Wasteland might be nice, considering how popular nonbasic lands are.

Tezzeret the Seeker for ramp and tutoring your mana rocks.

Ravages of War for another Armageddon.

Paradox Engine is pretty solid alongside mana rocks. With Knowledge Pool, since you're casting two spells, it gives you two different untap triggers, allowing for additional ramp.

cdkime: Excellent suggestions! I've added the suggestions to the deck and it seems to make it tick a little better. I have the same feeling about Storm Cauldron...I think perhaps Land Equilibrium would serve a similar role?

Nice list! I am tinkering with a build for her as well - here's my list. I welcome your feedback!

A few things I noticed about your list:

• I think the tax effects like Thorn of Amethyst and Sphere of Resistance are actually a bit of a nonbo with Lavinia, potentially making things like Mana Crypt and Force of Will cost 1, thereby escaping her counter. Conversely, Helm of Awakening is interesting tech to make 1 drops counterable by her.

• Have you considered Treasure Mage since it hits two of your main lockout pieces in Knowledge Pool and Omen Machine?

• How are you making Smokestack asymmetrical here - are you mainly relying on Crucible of Worlds for sac fodder? I think without some sort of token producer, it seems like it would do more harm than good. I think Tangle Wire does more work for less mana, by allowing you a temporary slow-down to find land destruction or other permanent stax pieces. You could also add Luminarch Ascension for tokens, which doubles as a win-con one the board is locked down.

• I also wonder if Teferi, Mage of Zhalfir does enough for 5 mana. Yes, he doubles as a backup, but it seems rare that we will won't have access to Lavinia given her low cost, and we get almost no value out of his "creatures have flash" ability. I'd personally go Paradox Engine before Teferi in the 5-drop slot.

Vukodlak: Good catch on the Thorn and Sphere. I do like the Helm of Awakening tech. Great suggestions overall and I've made the recommended changes. You're right about Teferi...and I'm also wondering if Ethersworn Canonist will affect me too. Let me know how the new revised list looks. I'll also take a look at your list later and give my feedback :)

I don't believe that is correct. Even though you tax a card with thalia or thorn or whatnot, it does not change the converted Mana cost. Taxing effects are additional costs, not what is printed on the card. Look at the gatherer ruling on gaddock teeg, it spells it out.

the_shawker thanks for bringing this up! I am and was referring to her triggered ability: "Whenever an opponent casts a spell, if no mana was spent to cast it, counter that spell."

This triggered ability is nullified by something like Thorn of Amethyst or Grand Arbiter Augustin IV - who we'd also love to run in this deck, but can't - because with these effects in play, now opponents ARE spending mana to cast their spells.

Note: this isn't talking about CMC the way her first static ability is. You are correct that her first is similar to Gaddock Teeg in that the CMC of the spell doesn't change based on how much mana is paid for it; all it's checking is the number of lands that opponent controls to determine whether they can/cannot cast it.

Really cool deck! Have you considered Sunder to slow your opponents down even more?

Clock of Omens can also generate you extra mana and allows you to tap Winter Orb/Static Orb on your upkeep to keep your lands from staying tapped.

I see you don't run many creatures, so you could go for creature lock-down with cards like Magus of the Tabernacle, Pendrell Mists (passive boardwipe with Winter Orb) ,Dream Tides, Overburden, World Queller, Spelltithe Enforcer, Ward of Bones, Portcullis and Crystal Shard I think are worth considering.

I play a blue/white superfriends deck that prevents anyone from playing creatures so I feel like some of my cards may compliment your deck xD http://tappedout.net/mtg-decks/grand-arbiter-and-friends/

Delay with Lavinia is a nice combo. Exile target spell permanently ;)

I suggest using Spellseeker for fetching Transmute Artifact then fetching to Knowledge Pool or Helm of Obedience.

I would also suggest Eye of the Storm. It doesn’t lock people out completely, but it does lock them out of instants and sorceries, while benefiting you significantly. It’s a solid redundancy, giving you 3 one-of cards that lock people out with your commander.

In my experience, helm of awakening can backfire if you cast a board wipe because everything else in the deck that costs 2 or more will be easier to cast. So whats the point of ld if you are going to let your opponent play 2 2-drops with 2 lands? Also path is bad here because you don't want them to have lands. Check out my slightly more budget list on my profile coming soom