Shard of Nightmare

Source
This item is obtained from the following order hall missions:
 * Powering the Portal: Andu'talah
 * Powering the Portal: Ashenvale
 * Powering the Portal: Azsuna
 * Powering the Portal: Kal'delar
 * Powering the Portal: Moonglade
 * Powering the Portal: Sylvan Falls
 * Powering the Portal: Val'sharah

As a quest objective
This item is an objective of Powering the Portal.