u/Beneficial_Can_4755

Tested just using the fireproof gem and uncrackable on all 3 and just activated them all 200 times (counted perfectly) and acquired all 3 during the next run after 200 activations. Hope this helps. You can upgrade them after you finish a run when having these in your deck. Tried quitting and it wouldn't let me upgrade at first.

EDIT: Wiki is fully updated now with how to get them. still glad I tested :)

EDIT2: 100 Duplicators, 200 Crowns, 25 Hollow hearts to unlock the next level of cards. Fastest way is to put fireproof on the crown and hollow heart and just combo them continuously in 1 turn.