Mysterious chronicle (part 17) is a book found only in Daemonheim. It may appear in front of the dungeon-ending ladder after killing the boss monster.
Written in the year 1693 of the Fourth Age. Bilrach efforts in creating the Furnished area for his workers to inhabit has established a powerful hub which will speed up progress. He contemplates using unstable methods to progress.
There appears to be contact with surface during this time.
Year 1693 of the 4th Age:
It turns out that I have been rewarded for my time creating the area above for my workers to inhabit, as it will serve as a powerful hub to the surface and help speed my progress. Even so, the fact that they fear the depth below is a concern. Thankfully, I can force a lot of the cowards, but I fear it won't be enough to make quick progress. The time may be coming for me to use some unstable methods.Zamorak be praised!