Bloodknife ter'angreal
From Tar Valon Library
A bloodknife ring is a ter'angreal which is used by an assassin which is also called a bloodknife. This ter'angreal increased their strength and speed and shrouds them in darkness. It is activated by touching a drop of the assassin to-be's blood to the ring. Once it is activated, it slowly leeches the life from it's host and so a bloodknife will be dead within a matter of days.
