[polly]

It's a FAI weapon. It has a holy theme, and it literally gives you +2 FAI (along side +2 WIL).

While it's transformation is solid on it's own, I don't see a reason as to why it can't cast Mercalan spells. I don't think it would be overtuned.

I'm not saying every FAI scaling weapon should be Mercalan casting tools, but I fail to see why Shine Sword isn't one.