The knife appears to be a well-made (masterwork) boot dagger.

The pages are made from processed mushroom fibers - something Dos has seen before - and the writing is in Goblin. Most of the early pages have been ripped out. Only a few pages remain, the last missive of a doomed warrior:

Spoiler: Journal & Map

This is the last testament of Coll Vinsen. If I have done well, you have never heard of me. I am the blade from the shadows, the silent killer, the anonymous goblinclan face that my targets overlook, not knowing that they see their killer. Long have I labored in the shadows, taking the blood money of nobles and officials alike, ensuring stability, delivering retribution, and settling scores before they turn to feuds.

I will say nothing more of my work, and have burnt the earlier parts of my journal. Let the survival of our people be testimony to what I have done, and let that survival continue! Whitemarsh threatens our very sanity. With support at the highest levels, I spent weeks reviewing mission notes, plans, maps, and histories. My conclusion was that an expedition to this hell-hole, this place of the twisted and trapped, that started him on his path to whatever he has become.

I must be brief, for they are outside. There are many dangerous things living here, but the raptors are the worst. They can smell me, and so I cannot elude them forever. I will finish this, leave it here, and then lead them on a bloody chase.

There are several one-way entrances to this place, including one near the Sphinxes' home. Great hidden ramps, traps that take unsuspecting creatures and dump them into the glowing pools that are one of the ways this place changes things. Many different species of what we call dinosaurs are here, from the giant Tyrannosaurus Rex to the Raptors that are my bane, and even the scavenging Swindlespitters.

Things that end up in the glowing pools for long, or that partake in too many crystals, are changed. They grow tougher skins and become harder to foil or kill. Some of them develop magic or extra senses. Most end up with hideous tentacles that serve as extra weapons, although I've found that they do aid in climbing. Worse still, we who have changed much cannot starve. We simply stay hungry. Too many predators, not enough prey. Only the dinosaurs that can protect themselves survive.

There are also blue crystals here that grow in the walls near the Rex nest. I slipped past them, and sampled them after seeing the adults feeding them to their young. When consumed, they take whatever you are, and make you even more so - I became faster, stronger, and quicker - but in doing so, you lose part of yourself. I am now more lethal than ever before, I cannot pass through the damned archways guarding this place! I am stuck here with the animals and the monsters.
(the remainder of this page is torn out)

(writing resumes on the next page in a calmer hand)
I don't know how Whitemarsh got out, but there must have been a way. Near each of the glowing pools is a glowing stone, harder than steel and the size of my torso. The glowing liquid seems to trickle from it. When I came near to the stones, I felt weaker, but free of the traitor's subtle call. They may be the key to stopping him, but getting one out and traveling with it without being twisted will be a challenge.

There are many dangers here. I believe that this place is some sort of trap. There are too many unpredictable fey and chaotic outsiders for it to be a coincidence. There is no balance here.

(A rough map follows)

Most of the dinosaurs - the ones without extra eyes - see poorly in the dark. I shall gather my strength, and when night comes I shall leave this place. The raptors have chased me for too long, and have gathered in force; soon they will risk the guardians I slipped past, and leap up the ladders. I do not want the information I have bled and will die for to be lost, so I will evade them and lead them towards their own territory in the dark. I will kill enough of them that my death will be swift and violent enough to prevent my coming back as an abomination. Perhaps I can kill enough that you may destroy their nest, and wipe them out. A runeforge and who knows what riches may await, in addition to vengeance for me.

May your spirits and minds stay strong, your feet light, and your resolve steady. Our civilization depends on you. Get moving!