You can slot her in the 99 of most decks that run creatures and shes well worth the mana investment
Just remember that umbra armor won't help if the creature's toughness is 0 or less, if it's being sacrificed, or if it's trying to leave the battlefield in any way other than by being destroyed
While we already have several cards that give you this same effect, Abandon AttachmentsAbandon Attachments has a few things going for it
The second win condition is Brain Freeze, which helps in strange scenarios where the opponent gains infinite life, yes, thats actually something you can do in PreModern, or when they simply have too many answers for Black Vise
Certain cards in the deck can help to discount spells, but this is only a band-aid to the bigger problem
Best mono white draw cards in Magic 21 30 Search the Premises : Increases artifact and token counts, and sets up draw power