I found Shiro's journal on his body after defeating him inside the Coalshire mine. I took it up to Raven Point where the gravedigger guy is and placed the journal on the grave. It made a cool effect and showed 4 trails of light circling up into the sky. And then nothing else happened...

I have to assume there was some point to putting the journal in this tombstone? Does it open something some where else? I couldn't find any way to interact with the tombstone and the grave digger guy doesn't say anything new. Does anyone know what placing Shiro's Journal on the tombstone does??