As mentioned in the above, rules on how to create stories for appentrices is a welcome addition. In our sagas they mostly act as lab rats or tools to drag their masters into trouble (and thus, stories). Tools for fleshing them out a bit, and running stories around them, might lead to more Player Characters taking apprentices too.
Personally i find grogs the least exciting to create - but they do tend to create the most entertaining stories. I have created and used a system for random generation of grogs (and for adding flavour to improvised NPC's) for quite a while now, in order to be able to make them on the fly. This saves us time fleshing out all the grogs of our Covenant, and tends to make them very different, in an odd and funny way. The most important grogs (do these even exist?) are designed using a bit more care, and with a full set of stats, though...
I'm suprised, but pleased, that they would make an entire book merely for Grogs. I had expected Grogs to share a book with Companion characters and their role in Mythic Europe - or perhaps teaming up with Apprentices. But with all those great Ars authors out there, i guess they just can't stop printing
Now the debate: is that a "natural form" of a magical cat or is the apprentice doing his Muto homework experiments with it?
And what house does he belong to?
My answers
[spoiler]He is casting a spell right now.
He is a Jerbiton. Merinita would have weirder features (green ears), bjornaer is out of the question, and that is not a weird-enough pattern for a criamon.[/spoiler]