It was similar to the Berserker's Bardiche, but is far, far rarer and is of considerably more use.
It was named for Silvani, who was a member of the UO team at this time, and was said to have a very odd way of pronouncing "Bardiche" which her colleagues decided to mock by including this artifact in the game.
It is very rare. It seems to have spawned with various collections of properties, but the common threads are Spider Slayer and Terathan Slayer. This makes it of more use than its relative the Berserker's Bardiche, because it lacks extra damage due to the opposite slayer property.