Chalice of Darkness

The Chalice of Darkness is a powerful artifact created sometime during the shadow war between Caramiza and Knurkang.
Filling the Chalice up with any liquid will turn the contents into dark, black swirling darkness. The less mundane the liquid is, the stronger the effect will be. Drinking from the chalice will then turn the person invisible - including the clothes and all the things they would consider to be "on their person".
The invisibility will last up to a few hours, depending on how much was consumed and how much of a tolerance the person had build up. The more often someone drank from the chalice, the more liquid would be needed to turn him invisible for the same amount of time.
However, when drinking too much of the liquid darkness, the person consuming it will not turn invisible, but into an intagible shadow. Unable to interact, eat or drink, they still have full mental capacity and will turn apparently insane quickly. There is no known way to reverse this condition.
There have been multiple chalices and it was used as an effective weapon for several opertaions against Knurkang. However, due to the sideffects, they were only used a short while and most of the destroyed.
Toi