Mulligans
Combo Mulligans
first play 1 shadowform because if you don't you cannot play Raza correctly. After that Raza , the last shadowform and finally keep Velen as much as you can on the board because with him you can deal 6 damage per turn for free.
Hello World, here is my first vision of the futur Priest shadowform (WHITOUT TGT , Blackrock ,The League of Explorers)