Cadaverous Leggings

Cadaverous Leggings is a leather leg armor popular with Rogues. It is part of the named armor set Cadaverous Garb.

Source
This item has a chance to drop from each of the six mini-bosses in Scholomance:
 * Doctor Theolen Krastinov
 * Instructor Malicia
 * Lady Illucia Barov
 * Lord Alexei Barov
 * Lorekeeper Polkelt
 * The Ravenian