Mask of the Mo Zing

The Mask of the Mo Zing can be obtained from Vael inside Grothmar Wardowns (right outside of Longeye's Ledge) for 250 Superb Charr Carvings.

Trivia

 * According to Guild Wars lore, a Mo Zing is a masterless assassin. Zenmai is one such assassin.
 * The mask resembles a balaclava, sometimes referred to as a "Ski Mask" or "Ninja Mask".