The Dirk of Disappearing

A short-sword once belonging to Knight Warden Darius. After the Eyes of the Archon discovered that he and Freia Greymoon had been killed, the item was taken from his body by Kasdri Valmorn, who soon gifted it to Nathaniel Lightheart.
It is a rather plain looking short-sword, with its most notable feature being its pommel. When twisted, the weapon turns completely invisible. With a second twist in the opposite direction, it reappears. 
Checks made to conceal this weapon are made with advantage.