Mysterious chronicle (part 28) is a book found only in Daemonheim. It may appear in front of the dungeon-ending ladder after killing the boss monster.
Year 118 of the Fifth Age:
While I destroy and carve through the land with a satisfying ease, the areas behind me are becoming alarmingly unstable. Just today, one collapsed and the interplanar shockwaves caused the earth about it to warp and corrupt. While this corruption is concerning, I refuse to be stopped. I move on and force the slaves who remain strong enough to come with me. I will not look back now, I leave my problems in my wake.Zamorak be praised!