Wondrous item, very rare, requires attunement
A small fairy door that grows when placed against a solid object and the command word is spoken. When you walk through you enter a small library but impossibly tall. It smells of an oak fire, old wood, and leather bound tomes. A fireplace crackles in one of the walls, with a cozy looking sofa in front of it and there is a reading desk on the other side. The walls of the library are mostly bookcases that extend seemingly indefinitely, with ladders to reach the upper shelves.
Inside an imp works as the attendant, sorting, organizing, and caring for the books. He has read most of them and will only serve someone who provides him with more reading material as he is endlessly bored. He fetches books for you when asked, that's about it.
Only books previously stored in here can be read, it isn't an endless library, but it does have a lot of information on various subjects. The DM will make a D% roll and determine if the book is already here.
| Rarity | Examples | % chance |
| Common | General bestiary for common creatures, basic geography, history, etc. Basic info on uncommon creatures. | 90% |
| Uncommon | In-depth knowledge on uncommon creatures, basic info on legendary creatures | 75% |
| Rare | In-depth knowledge of legendary creatures. Local/Lesser deities in distant lands, non-local history. | 50% |
| Very Rare | Lost or forbidden knowledge and magic, outer gods and cosmic creatures. | 25% |
| Legendary | High magic, ancient or cosmic knowledge, multiversal information Overgods. | 10% |