Archivist's cape

A caravan drove into an unknown Hall and stopped.
"That's it, from now on we don't know what's ahead," the navigator said to the captain. They both looked at the maps sprawled before them. Their goal was only about three Halls away, but the sudden influx of "newborn" Halls made the once simple travel way more difficult. And they didn't have time to wait for the scouts to check them.
The captain poked his head out of the cart and looked forward. There were another two carts in front of him. The doors to one of them just opened, and a young girl stepped out. She held a robe in her arms.
"Yuna, it's your time to shine!" the captain called out to her. The girl nodded in response and put the robe on herself.
Yuna's vision changed. The darkness didn't seem so dark anymore. She could see the road before them, and spots they should avoid. She climbed on the first cart, sitting next to the driver. From now on, she would lead them.

Archivist's capes, or robes, are an item acquired either from a corpse of an Archivist or their natural predators, the Cape-stealers. While it is possible to trade them, the ones in circulation tend to be bought very quickly by various organizations in the Dark Halls.

Appearance

While their shapes, sizes, and details vary, all Archivist's robes share some characteristics.
Before being worn for the first time, they are between 2.5 and 3 meters long. When put on, they will change their size so they are comfortable for the wearer. Unless consciously taken off, they will stay on one's shoulders no matter what, even when upside down. They all have hoods and no clasps, buttons, or zippers. There are slightly glowing, unique patterns embroidered into each one of them on the hood, back, and near all the edges.
No matter their texture, they all feel like living tissue to the touch. Some even get goosebumps or shudder in cold.
Each robe is unique. The materials they are made out of vary and can range from plant-like matter, animal leather and fur, textiles, synthetic materials, metals, and even minerals. But even in the latter variants, they still feel alive. They can be smooth, covered by hair, scales, feathers, bones, armor-like growths, spikes, and slimy (but mostly harmless) substances. The few legendary versions of them can even serve as armor or weapons. Their patterns and colors tend to somehow resemble the Hall from which they came.

Properties

As a piece of clothing, the robes are waterproof. Most of them don't protect from cold or hot, the only exceptions are the ones that belonged to the Archivists whose halls had extreme temperatures inside of them, but those tend to be way more expensive. They can protect from some slashes and some ranged weapons. If not completely broken, the cape will regenerate its durability after not taking any damage for some period of time.
Immediately after being put on, the Archivist's cape changes its wearer's perception. As long as they are wearing it, they are able to see in much darker places than humans could. Somehow, the cape increases the lower end of the range of perceived light. Additionally, it lets one perceive the spots where the light levels are too low to cross without being exposed to the hunger of darkness. From the description of the owners of the capes, it's very hard to describe those spots, and looking at them feels uncomfortable, but it doesn't come with any risk like looking at the "face" of an Archivist does.
Those who wear the robes can also manifest the "limbs" of the Archivist they belonged to. Said "limbs" can take many forms (and sometimes aren't limbs but body parts like eyes) and show up in one of three ways. They either grow out of the robe, spring out from underneath it, or float in the air around the wearer. The user immediately knows how to use them as if they were always part of their own body. Any damage done to them reflects on the robe.

Rarity:
Common to Legendary
Location/Drops from:
All of the Dark Halls/
Archivists and Cape-stealers
Category:
Clothes / Body+Legs Armor
Armor:
+1 to +3 / slashing and piercing damage,
0 / blunt damage,
more in the case of a Legendary ones

Drawbacks

"Why is it so angry?" a man shouted, barely avoiding a giant fist flying at him. He succeeded, but the rock that was next to him got crushed.
In front of him, there was an Archivist, his three other hands trying to catch the man's friends. Two of them managed to do so, and the blood of the last one covered the ground around him. The creature displayed unusual cruelty and wrath, chasing them for the last few minutes.
Another person died between its two palms, and the man's last comrade understood what happened.
"It's the robes! Take off the hood!" but before they managed to listen to their own advice, they got killed too.
As four fists flew towards him, the man ripped the hood off of his head. There was no impact. When he opened his eyes, closed in a reflex, he saw that the Archivist looked at him, leaning over him. Recognizing him as a human, it left.

There can be only one Archivist per Hall, so if one of them notices something that looks like them, they will attack it. They'll try to kill both the Mimics, which pretend to be them, and Cape-stealers, which hunt their species down. And if a human wears a robe of their kind within their territory, they might be killed too. The way to survive is to either not wear the capes in places with other Archivists or take them off before one gets killed. Once Archivists recognize the "fake" as a human, most of them won't attack them again.
It is said, that people who tend to wear their capes for too long start to grow cold. They will both feel and express fewer emotions. Soon, they'll start to seek solitude even if they used to be very outgoing. At some point, all of them walk out into the darkness. According to those rumors, their exact fate is unknown as no possessions or traces of theirs have ever been found.
What happens, in reality, is unknown as all who have heard those rumors limit their usage of the capes, and stop using them for a longer time whenever they notice the first symptoms show up.