WHY, WHY, EVERY TIME, EVERY TIME, EVERY TIME I TRY TO EXPLAIN OR COME UP WITH THE PROPERTIES OF A MAGICAL SYSTEM OR OBJECT IT ALWAYS TURNS SUPER COMPLICATED, FIRST I ACCIDENTALLY CREATED SOMETHING THAT WAS BASICALLY WHAT WOULD HAPPEN IF D&D'S MAGIC SYSTEM HAD A KID WITH QUANTUM PHYSICS, THEN I TRIED TO SIMPLIFY THE THING, BUT THE SAME THING HAPPENED ONCE AGAIN AND I COULDN'T USE THE SYSTEM FOR MY STORY, AND NOW THIS!!!!
Gah, now I should probably rewrite the properties of the book, it's basically an occult version of a school ipad at this point(which would probably have ended up being able to make more tomes. as for their ultimate origin, as the ice receeds ruins are unveiled some of which contain these tomes, typically with almost nothing in them but a few fragments), made by some ancient civilization to help their explorers and researchers, scan, capture/contain anomalies or creatures, and study the world at large. I might just make a separate post describing the properties. anyway, if it stays this way than whoever owned it previously found and caught something, something big, old and powerful. Something everyone in the occult world wanted.
The Book, which I will refer to as "the book of mers past" in the future, is basically a notebook containing the collective wisdom of countless generations of mer shamans, occultists, and explorers, and even some things which predate mer civilization. Originally these types of tomes were created by some long gone civilization the only thing separating the book of mers past from any of the other tomes of its type, are basically just the mers changing and hardlocking the language to their own, loading it primarily with their own teachings and findings, and changing the password.
In order to protect its knowledge from both people who don't deserve to have it(and to whom it is actively dangerous to read), and keep it from being destroyed it is immune to being damaged by water, burnt, being dropped, cut, and/or pierced. It is also written in mer meaning almost no-one outside the mer can even begin to decipher it, the instructions for use of the tome also encoded and even when translated incredibly cryptic most of the time. Unless you already know a thing or two about the occult, it just looks like a couple blank pages with symbols crawling across them, even if you could see the rest of the contents it would still be gibberish. In order to open for the first time one must cut their finger and let a single drop fall upon the lock while speaking the ancient shamans oath, and also being worthy to receive the knowledge and power it contains, as well as the responsibilities it brings. These instructions are actually on the cover, just written in mer, and heavily encrypted. As you use the book your connection to it grows, with things becoming easier and easier to understand, as the book in tern begins to understand you. The book of mers past doesn't by default, have pages in the traditional sense, rather to bring up a specific chapter, page, lesson, or function one must place their hand in the center of the current page and saying the word seek in ancient mer, while thinking of what you wish to access. within a chapter or lesson the pages work normally, with lessons only having the minor difference of being a recording made by an ancient owner of a tome.
Some pages (mostly maps and complex spell circle diagrams) are capable of expanding out if placed on a flat surface, they will continue to expand until they reach a set size, or when obstructed on any side, maps. Users/students can(and were heavily encouraged to) add new information, map data, spells, lessons, and knowledge to the book. There are three ways to do this, first, you can either write notes in the margin, which are keyed to fade in when certain conditions are met, or to record a new lesson, spell, or diagram on blank pages. You can write in the tome with any object or methodology, it just has to leave a mark, some students(and teachers) during sudden strokes of morning genius have used jam to record a particularly helpful note before it faided from their mind, and once written will look exactly like the rest of the text within, to erase simply swipe your hand across the page while thinking of what you want undone, this cannot be done to anything the person erasing didn't write. The second way to add things is to scan them in, you do this by, bringing up the scan function just like you would a page, then you point the symbol towards what you want to scan then press the symbol on the back, or on the page, in the case of document/s, you simply set them inside, close the book, then open it back up and remove the document/s. The final way is passive gathering, typically this just means that a tome will use what the user/s have seen of a place to create a rough three dimensional map. This book also serves as a tool for research, being able to passively collect data and observations, and able to use a function to capture anomalies (*cough* eldritch beings*cough*).
The whole basically indestructible thing is to explain why the past version of my character didn't just destroy the book before they were shot up nine ways from Sunday, and why it wasn't damaged when that happened. It is however too small to be used as a shield for anything except maybe your face or crotch, but when you put it into a fire it still gets just as hot, and it does nothing but pass on that kinetic energy it gets.
Now then, for the unfortunate part, and what makes this tome worth sending everything you have at a tiny village to get. You see, the previous owner managed to discover certain... secrets, a beast that simply knowing the name of grants power, both to it and you. He imprisoned it within the book, then began to use a function he created to take knowledge out of the tome, and imprison it in such a way that only holders of the tome of mers past could sense and thus scan, returning the fragments to the tome. But because of the raw power now contained inside the tome, that bearer was killed by other users of the occult. A fail-safe was activated by him nearing death, a fail-safe designed to protect the tome, to keep anyone else from getting their hands on the tome, by randomly teleporting him to an underwater field, there falerion found him, and found a note that told of the entity dwelling inside the tome and how dangerous it was.
Then Falerion picked up the book to continue the quest. Since the entity drew power from people knowing things about it, such as its name, falerion realized there was only one way this could end, his death, with him gone the entity would lose almost all power, gone forever, so long as the book is never reopened. Of course this didn't go according to plan, instead falerion merely had amnesia, and in some way still vaguely remembered some part of the entity, which due to being scattered then depowered, had basically lost all memory of anything before falerion reopened the tome. Also, current falerion may or may not actually be the entity or its host, which body hopped to, then used its last magic to sustain, him so that the entity wouldn't be forgotten
Yay, Wall of text which has me able to scroll significant amounts, number of actually combat useful things the book of mers past can do, zero. Well, I guess if we fight stuff made of paper, then I can just open up the thing and stuff them inside.