Neanderthal's thing isn't actually a quest, though.
Maybe somebody can take what he wrote and develop it further.
Quick bit o theorycrafting:
Clues.
My lord I have as you requested begun searching for clues to the Living Codex. The rumours are rife throughout the Stolen Lands as to this dread artifacts existence and unspeakable knowledge, and my work has taken me far and wide in an effort to track it down, such power cannot be left to circulate in the hands of the uninitiated, it must be harnessed, imprisoned or destroyed as you most wisely speculated.
I began my search with the seer Infinit, his knowledge is prodigious as all know, and I was given many clues as he stared into his orb of obsidian and groped it with eager hands. After many travails I came to Lord Jaesun's keep in Ultima Thule, and from there was directed onwards again with warnings as to my virtue. The Dweller would not even recieve me, he snarled of decadence and a new world he would create before sending me on my way. The Cloven Grimoire would not reveal its clues to me, insisting that I was not worthy, should adjust my alignment and get goodness. I admit after so many false trails I grow tired and dispirited, but one rumour that will not rest is that of an underlord residing in the dark down under where I will and can not go.
You are however not alone in your quest to find this artifact, a secret organisation waits and watches for it, dull, earnest fellows who have consented to come to your halls and counsel with you on finding the thing. You will know them by their strange headwear and the courtesy with which they treat the fairer sex, a respectful m'lady is never far from their lips.
Quest.
You meet with the Watch who wish the Codex contained or destroyed for they hold that its knowledge is tainted and far too exciting, they give you a ring that when equipped will identify you to certain individuals (the ones mentioned above or other Codex luminaries) and get them to reveal what they know of the Living Codex. Slowly a tale emerges of many erratic but insightful minds pooling their knowledge, but with each step along the path you are challenged by weird foes, mostly lusty red devils that spawn screaming and laughing from the darkness to hurl themselves at you, while chittering mockery and ridicule.
Conclusion.
Eventually you find Master Phillipe, a bibliophile who is penning a great work, and your characters will be rewarded with his patronage, a great deal of lore and a source of knowledge that is second to none. He will not admit to his work being the Living Codex, and the player will not be able to advance the quest beyond this point, and may assume if they wish that this is the end and the Living Codex quest has reached its conclusion.
Epilogue.
A madman (/woman?) is brought before you in chains...
Perhaps a conclusion where the Watch attacks you for harbouring the Living Codex, or the various prominent individuals you consulted in your quest are revealed as the Codex' makers, but the cannot contain the mad thing it has becoming as it switches to alternate personalities and forms.