Snake-like warrior monsters in
Terry Goodkind's
Sword of Truth series. They have capes that allow them to become invisible when the hood is worn up and fight with three bladed knives in each hand. They originated from the time when a great war was going on between the old and new wars and were created by
war wizards of the Old World, now they follow a dargon like creature that lives in the sewer system of the Palace of Prophets.
In
Stone of Tears,
Richard (the
Seeker) is attacked by one these while meditating in the Hagen Woods (a forest outside the
Palace of Prophets), sensing the attack he kills the mriswith, a great feat seeing as how nobody has done it in over 3000 years. As a prize he keeps the cape, not knowing its powers yet. Once Richard does realize the cape's true abilities he never goes anywhere without it, however eventually he does figure out that the cape is a
Bad Thing and discards it (I'm not gonna tell you why, read the books!).