With over 50 million HP, it takes well over an hour to defeat it, even with a high level party
I know Geier Reach Sanitarium is generally cooler because it forces discard for your Megrim shenanigans, but for these kinds of forced draw decks, Mikokoro, Center of the Sea is just as good
Play Boosters contain 14 cards, with one non-playable card
Other notable inclusions in the new expansion will be new Tera ex Pokmon cards for classic Pokmon like Forretress, Slowking and Dedenne, thereby enabling them to be immune from damage whilst on the bench and gifting them new abilities and stats
This can confuse combat math and make the counter feel less bad
You can of course, make the deck your own by exchanging some of these cards for others, so long as you stick to the rules about each card being unique, and fitting in with your commanders colour identity