I found that going debuff with Priestess Elaria works really well. The one cost pierce summon, 2 one cost Providence +2, 1 zero cost weaken +2, 1 zero cost feeble +2, 1 zero cost heal +2, 1 zero cost Devout Oath +2 (sacrifice hp to give all summons 1 faith). And as many 0 cost Elven Fortune as you can get.
Turn one summon 4 pierce pets, sacrifice hp, then you kinda just spam the 0 cost weaken, feeble, and heal, get them again with Providence, use them again, use the second Providence, which gives you those 3 cards and Providence back, repeat. Refill energy with Elven Fortune. Usually you win turn 3 or 4 full hp. Agony or Winds of the Vale skill best.
Prioritize upgrading Providence to +1 (just so you can do a weaken and feeble or heal and feeble loop), Devout Oath to +2 (reduce it's health cost), feeble to +2, heal to +2, Providence to +2. Getting the +1 energy upgrade from bosses is best. Though you could get the +80 max hp from boss 1 if you're unlucky and not getting all the cards you need.
You could also replace the weaken with a second 0 cost feeble card, if you're confident in surviving long enough to get all the cards you need.