Spoiler (click to show/hide):
So I rolled luck for ya and ya got a 10 for the roll, so you're going to get some answers
You don't exactly find any notes. But rather, as you explore about, you get... impressions on your mind. Feelings that once upon a time the gemstone was a purer color and hue, and it was under the sway of your persona, Carmen, of the Lovers Arcana. Then something came in and tainted it and the others, which seemed to create Kamoshida here. So it wasn't actually the same Kamoshida... but well, these impressions, glimpses of understanding, also told you killing him here would do no good. He'd just rejuvenate and return. At best, it'd give you a day without him present, but it'd also make you public enemy number one.
However, because the gemstone is tainted, you would have to link with it and fight the corruption within. And it would be a challenge. Worse, if you lose... you would
permanently lose some of your willpower and thus be weaker to Kamoshida's influence. And if your willpower sunk enough...
You'd truly become his Bitch Queen Slut Doll Fuck Kitten.