Friendly (Game Term)
A friendly object is one which is currently controlled by the player, or players on his team (in a multiplayer game).
Mage (Game Term)
This creature is a Mage, and represents the player in the game. The Mage can channel, cast spells, and has a special quickcast action each round. The Mage is a Level 6 creature. If your Mage is destroyed, you lose!
Controller (Game Term)
Each spell or object in the game is controlled by the player who cast it. The controller may use and act with that object and makes all decisions and choices for that spell or any abilities that object may have. Exception: Equipment is controlled by the Mage it is attached to.
The Mage represent the player or the Mage is a creature controlled by the player?
So, to answer your question, both are true. The Mage is the representation of the player and the Mage is also controlled by the Player. You could think of it as the Mage controls themselves. Nobody else is giving them orders. Thus, the Mage is indeed friendly to themself, because who else would possibly be their controller? All objects are inherently friendly to themselves, actually, since the only requirement for being friendly is to be controlled by the same person. So, your question really is whether any other creatures are friendly to the Priestess because she HAS to be friendly to herself. She can't have a different controller than the Priestess has. But, I don't think anyone is going to argue that the Priestess lacks friends who fight with her.
I hope that makes sense. I'm recovering from surgery and may be a little doped up on pain meds, lol.