The Rush'Kah is a special ceremonial masks used by Shadow Hunters.
In olden times, Shadow Hunters donned special rush'kah masks when performing ceremonies. As they travel throughout the lands of Azeroth, many Shadow Hunters wear these unique ceremonial masks to cover their features and inspire fear in others.Template:Cite
Currently there are no in-game Troll Shadow Hunter that uses the Rush'kah there are only other wooden masks.