The Books of the Holders were an accident. A young student of wizardry, Wormmark the Needful, had spilled his tenth pot of ink copying scrolls for his master. The master, whose name has been forgotten in history, locked the boy in a small room and gave him an accidentally impossible task: "When you've catalogued all of the magic items, you can come out." What he really meant was all of the magic items in the small room. What Wormmark created, however, was a book that self catalogued magic items.
The book does some very impressive magic, too. First, it is self replicating, self creating, and self writing. Each time a new magic item is created within 10 miles of any copy of the book, it records the item and follows it as long as it exists. If something important happens with the item, the book records the items uses and deeds, who wields it, and where they are. Some copies of the Books of the Holders follow just one item. Some follow minor items, giving them a sentence or two and that's it. Some copies of the books have become rather fond of one or two items and go so far as to draw elaborate pictures of them or even write sonnets about them.
Glacier looked at the massive vault and gave a low whistle. "I never knew the library was so... huge."
The librarian smiled. He got that a lot. "It grows."
Then a new thought occurred to Glacier and he asked, "So, how do we find Dragus in this mountain?"
Again, the librarian smiled. "Well, you are allowed to look freely. We do not charge the public. But if you want to hire a few of us, we can expedite your search. We have a number of young librarians who are familiar with these tombs."
The Library Business
Of course, it costs a great deal to maintain such a library. Ever expanding, a team of Dwarves are ever carving out new halls for the books. Librarians spend lifetimes reading and keeping track of their areas of the library. A whole cadre of guards are kept to ensure the safety of the books. And then there are all of the support staff including cooks, maids, cleaning crews, and more.
The Library brings in money in three ways.
First, it takes payments to search for items and their holders. They have guards and wards everywhere blocking spells of finding and discovery, and each wears a circlet that prevents their own minds from being read. Also, no book appears any different than any other book. The books re-shelf themselves the moment someone lets go of it. Paying for their services makes the task possible. An individual's chance of finding specific information in the tomes depends upon their intelligence: Extreme gets 1% chance per week of hard labor research (at least 10 hours per day) cumulative, average 1% per month, and low 1% per year. Thus an extremely intelligent person could find information in 100 weeks or less. For each person in a team doing research, give the most intelligent member of the team an additional roll in the time period. If the Librarians are searching, they have a 1% per day cumulative chance. The rate they charge is negotiable: they may want more gold at 100 ounces of gold per day of research per Librarian hired, or they may want a specific item from the person, or they may require a service performed first. Once the price is set, however, they will not renegotiate.
Second, some holders of magic items pay the Library not to find them. Again, the price may be negotiated, but the Librarians do not go back on their promises. However, some of the wording on these promises allow some flexibility, and the Librarians are quite favorable to those who are of most service to them.
The third way is that the Head Librarian occasionally commissions a group to go and collect a certain item of great value. The Library actually has several valuable items in store and does a good business selling these. They even have a "gift" shop which stocks many small items that no longer have holders.
Treasure hunters from all around come to the library seeking information that will lead them to great wealth. They open a book, find where a magical item is and what holds it currently, weigh the risks that they know (the books record the holder, but not their allies or other defenses), and if the chance looks good they head out. Soon their attempt to take the item is recorded in the book and the cycle continues. On any given day in the library there will be 1-12 new adventure seekers, 1-6 veterans, and 1-4 guild members (for instance, a researcher for the Thieve's Guild looking for a mark.)
This fact of their clientele has led to a rather drastic set of rules in the Library. Knowing that many come who are simply seeking wealth and may be inclined to steal, the librarians have a few rules:
1) Steal nothing within these walls.
2) Harm nothing within these walls.
3) Protect the Library forever.
Upon entering the library, each person passes through the great arch and over the great seal. This binds them to the rules of the library. Should a person attempt to circumvent the rules, their memory is erased. Typically this just means that they forget what they were about to do such as steal a purse. They won't even know that they have forgotten it. If their intention is very strong, the forgetting is even stronger, possibly causing them to forget the past year of their lives. And in very rare cases where the library feels threatened directly, the curse causes the person to forget everything, even how to breathe.
Just over a hundred years ago, a terrible mage called Promus determined to take the Library for his own. He had been inside and seen the books and determined that it should all be his. His powers of Necromancy were phenomenal, and he knew the weak librarians were no match for him. Promus raised an army of undead and marched on the Library. Then, only a mile from the Library, Promus turned on his own army, fighting them and destroying each and every one of his creations. He then spent the next eight years building a tower and walls and manned them with bound undead, determined to protect the library forever.
And he died of old age never really able to explain his change of heart.
Since this is passive, very few even know it exists. It is not uncommon to see someone who was coming to the Library to steal standing just over the great seal with a blank look on their face wondering why they are there. So, despite the Library's great wealth and rather dangerous crowd it attracts, it is generally extremely safe.
What's This Thing Do?
One of the most common uses of the Library is for a person to come and find out what their new acquisition can actually do and how to make it work. By finding themselves in the books, a person can find their item and its full history including major uses of the item, key words spoken, and so forth. While much of this can be determined by a wizard's magic, the Library is far more complete and reliable.
Showing an item to the librarians will allow them to find its book within an hour. While the item is within the library, all books containing mention of it will glow with a colored light that will also glow around the item itself. Once someone discovers this they have a far easier time conducting their own research, typically reducing their own searches to 1-4 days total.