Mysterious chronicle (part 22) is a book found only in Daemonheim. It may appear in front of the dungeon-ending ladder after killing the boss monster.
It was written in the year 1911 of the Fourth Age. Due to the magic in the air, Bilrach is unable to keep portals to the Spirit Realm, home of the gorajo, closed. He decides to ignore them and proceed to the Rift instead and will deal with them later.
Year 1911 of the 4th Age:
Curse the gorajo! The air here is turgid with magic, and no matter how many times I close the portal to their realm, another reopens. I've decided to forge on; those pathetic creatures will pay later. I will reach the Rift soon and come back to destroy them once and for all.Zamorak be praised!