Leggings of Forgotten War

Source
This item drops from the following NPCs in the Jade Forest of Pandaria.
 * Urobi the Walker
 * Aethis
 * Ferdinand
 * Morgrinn Crackfang
 * Kor'nas Nightsavage
 * Mister Ferocious
 * Sarnak
 * Krax'ik