[The note isn't in his handwriting. It's pretty obvious what it is, though - the secrets motive from a week ago. The one he's laughed at, before reading his note. The note lists three secrets.

1. Arthur and his guild worked to enable the use of a weapon that will obliterate Etria and the surrounding area completely.
2. Arthur and his guild murdered Visil, beloved chieftain of the Radha and leader of Etria.
3. Arthur and his guild committed genocide by slaughtering the Forest Folk.]