What about Ethereal Armor ? Also keeping in theme with your other creatures what about Loxodon Smiter ?

Thanks for the suggestions. I decided against Ethereal Armor because I wanted fewer, more powerful auras instead of many small ones. While Uril's ability is more powerful when using many low cost auras, I wanted to free up space in the deck for removal and the land destruction package. If I went the enchantment/card draw route for this deck, ie Argothian Enchantress Mesa Enchantress etc, I would absolutely use Ethereal Armor as well as Sphere of Safety which I have also tried and rejected because I typically don't have enough enchantments on the board. Loxodon Smiter is cool but as a 4/4 with no abilities I don't see him being very useful even if he's guaranteed to get on the battlefield

Darksteel Citadel

I feel like this setup is too mana intenseive (i.e., Sudden Disappearance with Uril out + mass LD), and would be more effective if it was focused more on surviving mass LD better than other decks. Putting in more mana rocks would be a good way for you to ramp up and destroy all lands in the first 4 or 5 turns, and then be out ahead by 2-5 mana while everyone else is at 0.

I would probably take out Ghor-Clan Rampager , Intimidation Bolt , Sudden Disappearance , and Fires of Yavimaya , and stick in a few 3 CMC rocks like Chromatic Lantern , Coalition Relic , and maybe also some signets. You could probably take out another land or two as well and get 4-5 more mana rocks in the deck.

Lastly, Mayael's Aria could be an effective alt win con if you have Uril out but can't get him through for damage.

Also running fetch lands, even cheap ones like Evolving Wilds , is pretty effective with crucible.

Also Strip Mine is a nasty combo with crucible, especially with Burgeoning out.

Goodbye and good riddance, Karmic Justice!

Hello to my new friend, Stranglehold!