For all those having trouble with the ??? fight:
In my experience, she tends not to use the Cruel Destiny move (the one responsible for the crash) unless you're smaller than her. So, obviously, going in with even more height will insulate you (somewhat) from that. She also can't crash your game if she never gets a turn--stunning her with Eye Of The Storm (legendary rarity, found in Base Set packs) can keep her locked down long enough for you to chip her away. You have exactly enough MP to cast Eye Of The Storm and Rapid Recovery on the same turn, and you can use the Rapid Recovery to return Eye Of The Storm and a second Rapid Recovery to your hand, letting you loop her forever.
Of course, the seven damage from Eye Of The Storm is never going to get over her regeneration, so you'll need to be able to play other cards. You'll also run out of cards in hand eventually, since Eye Of The Storm requires you to discard a card as well. Enter Boundless Mana. Found in Coven packs, it applies the Mana Confluence buff for three turns, which gives you an extra 2 max MP and causes you to draw a second card at the start of your turn. Fighting her on New Game Plus is also highly recommended, since it gives you access to the incredible card Galatea, Endbringer. The Breast form gives you a permanent +5 Max MP and some other stuff that's nice but not necessary for this fight, and if you play her enough times, you'll get a True Stomp, which should kill her dead in one hit. She's tough to resolve, given the 10 MP cost, but that's why the deck should be full of any and all ways to stack MP growth. And a little RNG to push past a couple of turns, and just hope it doesn't blow up in your face. You saved before you started the fight, right?
The deck I used to beat her:
- 4x Intimidating Aura
- 1x The First Giantess
- 1x Eye Of The Storm
- 2x Reckless Greed
- 1x Dark Contract
- 1x Reversal
- 1x Astral Alignment
- 1x Mana Flooded Fairy
- 1x Boundless Mana
- 1x Unbreakable Resolve
- 1x Galatea, Endbringer