Additionally, secret rares which include Special Art Rare (SAR), Ultra Rare (UR), Super Rare (SR), and Art Rare (AR) cards are not included in the main set count (the denominator)
If you sacrifice it, you get to destroy an artifact, enchantment, or even proliferate, making it an excellent choice for counter-based decks
He is fairly pricey and doesn't do much to protect you against mass removal which is your biggest concern against slower decks
Here there's basically one way: put it under an Oblivion Ring and then cast Apocalypse
True, replaying the adventure again and again does give you lots of Y'shtola triggers, but it has me wondering whether there's a token subtheme to the deck, or if Hildibrand's ability is only meant to buff his own zombies