This "magic item" is in fact mineral found deep within a mountain. An incredibly rare silver, that was born from the compressed and decaying corpse of an archdemon. This silver is inactive until it is used to kill a celestial, or abyssal creature. The forged silver will lay dormant until it is satiated. The silver is satiated upon consuming 5 total souls of celestial or abyssal creatures.

Once all 5 soul shards are filled the weapon awakens and become sentiant. The nature of the sentiant weapon is determined by the balance between souls consumed, leaning towards the majority in its nature (eg, more celestial or abyssal/ Good or evil). The silver cannot be enchanted due to it's innately powerful magical nature. Instead the weapon, silver scales with it's consumption of souls. +1 for the first soul, +2 for the fourth and +3 for the fifth. The traits, effects and nature of the sentiant weapon are to be determined by the DM after it awakens. (The number of souls required to satisfy the weapon can be changed as well depending on the nature of your campaign; however, the number must be odd, to determine which nature is dominant, celestial/good or abyssal/evil). 

The most crucial part of the silver is lost to lost and as such is abyssian silver is often used for the creation of fine trinkets or armor. So most people see it for it's incredible value and not it's unfathomable power.

**It is important to note, only master Smith's have the capability to fashion anything out of abyssian silver**. 

I hope you all enjoy use of this awesome rare material in your campaigns as much as I do in mine. 

Notes: Only weapons made of this material require attunement.