The book found in this room is but a translation of a translation of the original Pnakotic Manuscripts, as a DC 30 Knowledge (arcana) check can attest. Of course, since the original text (said to be written thousands or perhaps even millions of years ago by an unknown race) is long lost, the fact that this book is a copy of a copy isn’t all that unusual.
Written in ancient Aklo, this copy of the Pnakotic Manuscripts focuses on magical portals, teleportation, and conjuration magic in general. The book itself is relatively large, weighing 10 pounds and consisting of about 500 pages of thin parchment. The cover bears a large inset crystal (said to aid in concentration during the casting of complex conjuration magic) and a series of metal insect-like clasps along the edges lock down and keep the book from being opened by anyone who can’t make the DC 25 Intelligence or Disable Device check to do so.
Once read, the Pnakotic Manuscripts grant a +4 bonus on all Knowledge checks made pertaining to conjuration magic or the gods and magic of the Old Cults. In addition, the book functions as a spellbook and contains the following arcane spells: gate, greater teleport, greater planar binding, interplanetary teleport (see Pathfinder Adventure Path volume #14, page 54), lesser planar binding, planar binding, plane shi!, teleport, teleport object, and teleportation circle.
The inside cover of the book bears the following inscription: “May we, the Keepers of the Oldest, prevail over the scourge of simplistic thought and lesser men.” Beneath that are five signatures—the names of the five Keepers of the Oldest (see page 12). One section of the book is marked by a red silk bookmark—indicating the beginning of a relatively lengthy discussion of how to use special rituals to open portals in key locations. This section has been heavily annotated in the same spidery script on the inside cover (a DC 20 Linguistics check matches this handwriting to the signature of “Keeper Crove”). An hour of study is enough for a reader to deduce that these “Keepers of the Oldest” were hoping to use the ritual described in the book to try to open a portal in the Sunless Grove to contact “spawn of the Dark Tapestry” and further enhance their knowledge of forbidden magic and arcane secrets.
A section near the end cautions those who would attempt this ritual, warning that forcing open such portals draws forth the spiritual essence of the casters, and that any entity contacted by the portal can make “hideous use of this essence by consuming it, growing more powerful in the bargain, such that only the end of such essence can challenge the intruder’s rights upon your world.” If the players can’t decipher what this means, a DC 25 Knowledge (arcana) check is enough to correctly interpret this warning: opening a portal in this manner links the souls of those who open the portal to a creature on the far side, and the creature will grow more powerful if it can kill those who conjured it. Conversely, if some other agent kills the conjurers (or sets their spirits beyond the reach of the conjured creature), that spiritual energy will be lost to the conjured creature. In this way, it should be possible to weaken a summoned creature by killing the conjurers before it can do the same, and if all involved in the summoning can be killed before the creature gets to them, it would be banished back to the Dark Tapestry.