Librarians are a humanoid type stray with long limbs, tall, slim body, and an unnaturally small head.
They are approximately 2.5 meters tall. Height is consistent across all Librarians. Librarians wear no clothing, and their skin texture looks distorted. All Librarians have a dark brown skin consistent to bookshelves in Level 2. This feature allows them to hide in plain sight.
Librarians are eager to have conversations with wanderers and strays. They show no hostility or aggression towards anyone unless they break the Rules of Library. They willingly help wanderers and strays on retrieving books from bookshelves when asked. If a wanderer or stray show hostility towards Librarians, they turn hostile and don't stop until the threat is neutralized. They show unnatural strength and adapt their strength depending on what or who they're fighting against.
Unless being interacted with, Librarians seem to try to organize bookshelves, resupply food and drink, and even do research on their free time.
It is reported that Librarians go into a sleep mode after 8 hours of active time. Sleep time is 2 hours in every case. They go out of sleep state when disturbed before 2 hour time is up.
I was trying to solve the puzzle to head to Level 3. I asked help from Librarians. They were willing to help me. As some of them were searching the bookshelves for the books I requested, some idiot made noise. There were some Librarians that looked like they were sleeping. The ones that are helping me didn't respond to the noise, but those who were sleeping started running towards the noise. All I heard was a death scream, and a torn apart body flew in front of me. I prayed at that exact moment...