Traditionally, these cards could shape your game on entry, and Brightglass Gearhulk is no exception
Millstone is the origin of the trading card game "milling", which is basically to moving cards out of your opponent's deck into somewhere less useful (typically the graveyard), and denying them resources that they could use
It can be any doctors companion, which is this sets partner, and since you can choose its color, its a free color to a given doctors EDH deck
DH: I think its safe to say youll see some characters making multiple appearances in the product and each is appealing to different kinds of players
Its passive ability lets you flip a coin anytime your opponent attacks
For four mana, you get a repeatable blink effect allowing you to get extra value out of your creatures