The last Acervo, probably

According to the team in charge of 0125-456-112, the young woman that took part in the foreseers hunt wields an acervo. That's twice unusual, since we had no record on any living acervo, and every record and tale about them say that it's close to impossible to make a link with those objects.
I can't imagine how this one —probably the last of them— survived and fell in the hands of a murderer from a world where anything remotely similar to magic is rejected and destroyed.

History

Acervos were already rare in the Light Caves in the early years of Discovery Age, and the only reason there were some that still worked, was because nobody seemed interested to use them as anything but decoration, because they were considered inconvenient tools and slow weapons.
Sta Nidauvie magic is almost as fast as thought and understanding an acervo was difficult, so they didn't became very popular until after the Light Caves discovery, when conquerors from the Eight World found out that, used as weapon, an acervo stole the victim's life energy, and therefore any wound would be lethal, no matter how small.
Most acervos were destroyed the first time a conqueror tried to use them. Others became powerful weapons until they were broken in battle —or when they changed owners— and ended in famous museums or storage buildings in Kren, the Eight World, and Society's facilities.

Mechanics & Inner Workings

Designed to emulate intelligence and carrying their own magic, acervos can take whatever form and properties the owner needs, as long as said owner knows exactly what they want and how to communicate it to the object. Without a proper understanding, the acervo can be useless or get broken.

Classification:
Enigma

Item type

Magical

Rarity

Extremely rare (Thought to be extinct lost).

Weight

Changes to suit (or to annoy) the user

Dimensions

Changes at will (the wielder's will, most likely)

Base Price

I'm not even going to dignify that with a response

Raw materials & Components

Starglass is the only known material that could explain the crazy amount of energy the acervos can hold. Besides, that thing is really malleable, with the right magic, it could change form the way acervos do. There is no way to prove it though. They change their properties to the point that they seem to be of different material, even the broken ones show completely different components.
What we know for sure, is that living acervos are charged with some kind of magic that emulates intelligence.