Librarian

Librarians are Wizards who have dedicated their lives to knowledge and the understanding of the unknown. Documenting their acquired knowledge through the pages of their spell book.  Their innate curiosity and nigh obsession for gathering knowledge links them to an entity otherwise known as "The Library", a seemingly endless collection of literature maintained by other Librarians, to preserve the knowledge acquired by themselves and their peers. 

Level 3: Thirst for the Unknown

You can choose to gain proficiency in Arcana, Religion or History. Additionally, if you spend a long rest studying a magic item capable of casting a spell, whether it is in the wizard spell list or not, you may copy it into your spellbook. This spell must be of a level you can cast. 

If the magic item can cast more than one spell, you must repeat the steps for each spell, and the item becomes unable to cast the spell you copied. If you copy all spells from the item, the item forms into text and is absorbed into your book, becoming an entry on magic items.

Arcana

Gain Proficiency in Arcana

History

Gain proficiency in History

Religion

Gain proficiency in religion

Level 3: Ink and Quill

Your profane interest in what you do not yet know has imbued your Spell book with power and linked you to it. 

You gain the following:

• If the Spell book is within the same plane of existence as you, you may expend a bonus action to teleport it directly to you. 
• Now that you and your book are linked, you are able to perceive through the book. By expending an action, you see directly through the book as it shares your senses. However if the book is on another plane of existence, you can neither hear, nor see through the book. It instead transcribes It's surroundings in your minds eye. 
• Being an expert in scribing things into your book, when you copy a spell into your Spellbook, It takes one hour less and costs 15 less GP. 
• While someone is speaking, as long as you can hear them clearly, you can focus as your book transcribes what they're saying exactly. 

Level 6: Endless Pages

Your connection to The Library strengthens. You yearn for the day the entity deems you worthy to enter It's halls.

You gain the ability to expend an action and be absorbed into your book. While absorbed, you gain the following:

• Your movement speed is reduced to 0.
• You may expend an action to attempt to draw creatures to your book whilst using this feature. The creature you're attempting to draw must succeed a Wisdom saving throw, against your spell save DC.
• You are able to perceive your surroundings through the book, using sight and sound. 
• Anyone attempting to locate you whilst using this feature will need to roll against your spell save DC. If successful, you are immediately spotted. Anyone using Detect Magic around you whilst using this feature, sees the book brimming with magical energy. 
• You are unable to use any spells whilst using this feature. The exception being if someone grabs you, you may cast a spell with a range of Touch. Or if someone opens the pages, in which case whichever direction the pages are facing, the spell is cast towards. You cannot open the book yourself whilst using this feature.
• If someone opens the book, you may communicate with them through text, your thoughts being transcribed onto empty pages. Additionally, you may shuffle the pages to a specific section in your book, or force it closed. 
• You may end this feature whenever you wish, coming out of the book. Or you can choose to appear out of another book within 60ft of your spellbook. Expanding an action to do either.

Level 10: The Door Opens

The Library has read your entries and recognizes your desire for knowledge, granting you access to It's endless halls of bookcases.

• You gain the ability to visit The Library, The Library is an endless hall of bookcases, shelves, cupboards, study areas and lounges. This ability acts like the Mordenkainen's Magnificent Mansion spell. 
• To be able to use this feature, you need your spellbook with you. When you use this feature, your spellbook rapidly expands into the shape of an Oak door, once you have entered, the door the closes behind you and disappears.
• You may choose a maximum of 4 willing creatures to be allowed access to The Library with you.
• You may also choose one unwilling creature to be forced into the Library with you. The creature must make a Wisdom saving throw against your Spell save DC in order to prevent this. 
• You cannot bring willing creatures and one unwilling creature at the same time. 

Should you decide to bring an unwilling creature or a willing creature, It is your duty as a Librarian to declare the rules of the Library. 

1. The Golden Rule: Silence : Creatures within the library are not allowed to cast spells with Verbal components, additionally, any actions, spells or cantrips that cause loud noises fall under this rule.
2. Handle With care : Creatures within the library are not allowed to destroy the objects or items within the library, or alter the environment inside the Library.
3. Respect The Library : Creatures within the library are not allowed to leave with any items found inside the library. Nor are they allowed to read any of the books without a Librarians say so.

Breaking any of these rules willingly, results in the offending creature being absorbed into a random book inside the library for 1d4 rounds. After the rolled amount of rounds have passed, the creature is ejected out of the library with their movement reduced to 0 until the end of their next turn.

 You can use this feature a number of times a day equal to your proficiency modifier and all expended uses are regained after a long rest.

Level 14: Chapter 7, page 365

The Library has become one with you and your Spellbook. You are documented into the Book Of Librarians inside the Library and can feel the entity congratulating you on your long and harsh journey.

You gain the ability to introduce the rules of the Library without the need of being inside the Library. The Rules are tweaked to fit the environment you are currently within.

Any creature within 60 feet must make a wisdom save against your spell save DC. If the creature/s fail, they are subject to the rules of the Library. You can decide which creatures are affected by this ability.

This ability lasts for 10 minutes.

Once a rule is broken, the offending creature/s must each make a Wisdom saving throw against your Spell Save DC. If they fail, the following happens:

The Libraries door appears in an unoccupied space and opens. The offending creature/s are changed into paper before being forced within the library, and are trapped for 1d4 rounds. Each creature must be rolled for separately. Once the amount of rounds rolled has passed or the ability ends, the creature/s are expelled from the Library and have their movement reduced to 0 until the start of their next turn. 

The creature/s trapped must spend their turn making a Wisdom saving throw against your Spell Save DC. 

You can use this ability a number of times a day equal to your proficiency bonus. All expended uses are regained after a long rest.