Excerpt from 凌舞 - Shinomi - Eclipse Dance
"[...]
A typical Unknown. You'd think it's a book, right? You'd only be half correct if that's what you thought. A Unknown is just an object that contains information. What kind of information? Any kind, really. But we're not interested in random data. We're talking about Grimoires for magic! As such, what kind of Unknown does Shinomi have? If you've been following along, you've actually already seen mentions of it. That's right! It's the Stone of Wisdom. The very Gem Unknown that Shinomi fused into their skull.
I wasn't supposed to literally fuse myself with the stone… rather… acquire the knowledge contained within. Alas, I was foolish and had misinterpreted what the great alchemist Unknown meant by fusing it with myself. I was meant to truly become one with the knowledge hidden within, thus finding out the truth about eternal life. Now that wisdom is lost to me forever…
Or is it?
[...]"