MArcomage

Consecrated land 3/3/3
Holy
Wall = 150
Replace all cards in hand with Purified ashes
Stock: -N/10
N is wall gained

I'd rather that the amount of wall gained be capped at the amount of stock lost. With proper deckbuilding, it would be easy to recover from this, both in terms of the lost resources and the mass discard. Also, it seems that this would be equally useful in any keyword deck, not something that's only effective if you're playing Holy.

I think any card that gives potentially 150 wall for 9 resources and does not require any other conditions is a bit unbalanced. Even as a rare I wouldn't be sure.

Completely redid concept per suggestions, while retaining flavor.

New version:

Holy.
Replace all cards in hand with Purified ashes
Stock = 0
Wall: +N
N = resources lost

Even as a last measure, this card has quite a heavy effect on you:
Stock = 0 AND hand is useless

perhaps just replace all non-Holy cards in hand with Purified ashes? It would be still quite a negative effect to counter the high wall, but it would keep you in the game

An alternative to that would be selecting one card to not be discarded. That way, Auxilia could take care of the effect after an additional round of production.

I like Lord O's idea better for the Holy synergy, though.

Per Lord Ornlu's suggestion, the card now reads "Replace non-Holy cards".