Here's everything you need to know about MTG Cascade: How does MTG Cascade work
The more you win against them, the more of their deck youll have until youve unlocked the entire recipe
I can see this mechanic being a lot more useful in a Limited format, but its practically pointless outside of that
If your opponents load up their creatures to try to stop you, you can grind them out with Early creatures with eerie abilities, such as If you're looking to change up the deck, you could lean it away from being so focused on Auras and care about enchantments in general
Konami Computer Entertainment Japan (KCEJ)
If that wasnt enough power for you, then check out this guys second effect: When its destroyed by battle or card effect, you can search out a copy of Polymerization from your deck, and any other Ancient Gear monster from your graveyard