Don't ask me, that was his question. But basically, in his Heartbeast a Ward vs Animals affects him (let's forget about his own Parma for now), but if he changes into a bear with a spell he has the chance to get through Parma and such through Penetration. That's what he wants. Here:
The best thing to do is still to rely on your Parma to get through the Ward, and rely on the natural, non-magic nature of your Heartbeast to get through his Parma. If you can't get through the Ward with Parma, change to human, walk through then change back. Or drop the Ward with some kind of Pe Vim spell.
You actually wouldn't pit your Penetration against his Ward though no matter what form you were in (Penetration doesn't work like that), only your Parma would affect you to get through. And whether you're a bear by Heartbeast or spell, the Ward can work on you. If you're a bear by way of a spell though, what wouldn't affect you is a Re An spell that is meant to control animals, they would need to use Re Me.
So, essentially, for Bjornaer as their heartbeast: parma (+animal art score) equals magic might for getting through/ignoring a rego animal ward. And the heartbeast's attacks are mundane, thus not resisted by magic resistance. Which makes sense, on the face of it.
When transformed via muto corpus+animal, on the other hand: your parma is still pitted against a defender's ReAn wards, while the transformation spell's penetration are pitted against the defender's magic resistance?
An animal with magic might score uses that magic might score for getting through both rego animal wards and generic magic resistance with its "mundane" (ie non-power-using) attacks, right?
In sum, this reading is workable, but subtle enough to confuse anyone. Other readings are just as possible.
Against the "mundane" attacks, be they from Bjornaer magi, mythic creatures or ordinary animals, you only get your form bonus (Animal/5) as a soak bonus, which might be what you meant by "generic magic resistance". The attacker's Might is not involved.
Everything else agrees with my own interpretation.
I'm not sure about this statement. Parma could allow the Bjornaer to ignore a ward against mundane beasts, but it might not keep him from passing through a Ward Against the Beasts of Legends, which wards against beasts with Magic Might. Since Parma is not the same thing as Might, it doesn't necessarily apply in my opinion.
Probably not, because wolves don't have scimitars for teeth in nature. It would have to be a magical power that transforms the creature's teeth into scimitars, which means a magus could resist it, as I see it.
Depends on how you designed the creature. That's entirely a storyguide decision. In my book, unless specified otherwise, its teeth are mundane, even if no mundane wolf would have scimitar teeth. Erik's wolf has a power to turn its teeth into scimitars. That's a different creature design, and its teeth definitely aren't mundane.
