Mirror Fragment of Anashti Sul Keybind

The Mirror Fragment of Anashti Sul is an item that was introduced in The Broken Mirror expansion pack. It allows you to go back and forth from Sul Vius: Demiplane of Life and Sul Vius: Demiplane of Decay. In order to obtain it you have to complete a quest that starts from Quellious in the Plane of Tranquility.

That's really all there is to it!