If not, you might just want to have Spike grab a copy of Bitterblossom while shes at it
Furthermore, you'll have needed the Basic Pokmon down, the Stage One in your hand one turn, then the Stage Two in your hand the next just to get it into play
Much like with Kethis, the Hidden Hand, the key to Emry, Lurker of the Loch is going to be looping the recast ability
As for dual colours, eight are Dimir (blue and black), 19 are Rakdos (black and red), four are Gruul (red and green), five are Orzhov (white and black), one is Izzet (blue and red), 14 are Golgari (black and green), and six are Boros (white and red)
Check PriceCharting for historical context
Greven grows stronger and draws you cards for each sacrifice, creating a vicious cycle of aggression and card advantage