|The Shifty Mongoose|
I have absolutely no idea. Its description says it's "the mysterious intellect that guides the quill", and "it is said, from the Peacock Spirit itself."
That specifies nothing, so I guess that means it's up to the GM to decide how that goes.
How I did it, if it helps, is that it counted as a demigod, only wrote a check for "yes", an X for "no," a ~ for "maybe", and a ? for "I don't know." Also, since you just think of a question while holding the quill and it writes the replies on the nearest available surface, I ignored the chance of your INT & CHA falling to 8 for a couple of weeks. So far, it hasn't unbalanced anything.
I decided it was the Peacock Spirit - just because its worship has died out on Golarion doesn't mean the diety cannot answer - it still exists and is worshiped on other worlds, etc. And because I thought it would make things interesting, it was a greater god.
I was subsequently told in a forum post somewhere with a sense of authority that seemed valid, that while the game system provides different tiers of dieties, on Golarion, all the gods are Intermediate in power level.
|The Shifty Mongoose|
I tried to see if that was noted somewhere too, not finding an answer in anything printed, I ran it as a pure plot tool to help them move forward when they were stuck.
Roll the dice behind the screen, consult the chart, nod sagely and provide whatever answer works for the game. I waived the stat loss issue too, but didn't tell the players that, it kept them from using it in places other than in town where they were safe in case something happened.
I had it be the Peacock Spirit. My PCs ended up giving the Quill to the monks of the Therassic Spire in Kaer Maga, in exchange for all sorts of knowledge help for the rest of the campaign.
The Peacock Spirit also showed up in Runeforge with Vraxeris. I added a some unique magical properties to the statue in I2 that turned into a Peacock Spirit-flavoured encounter.
Having said that, the Peacock Spirit remains mysterious, the PCs were not able to figure out much about it. Which is good: we as GMs don't really know although i hear Return of the Runelords will contain more info on it.