Shade of the Evening is a thick, blue liquid made from the leaves of trees that sit outside the House of the Undying in Qarth. The trees are black-barked with inky blue leaves. It is drunk by those who enter the House of the Undying and the warlocks of Qarth, so that they may "hear and see the truths" that will be laid before them. If one drinks many doses over time, their lips will turn permanently blue. It smells like rotted flesh and has an oily texture and it supposedly tastes like all the tastes a person has ever tasted, and some that a person hasn't.
Pyat Pree is a character who has blue lips from frequently consuming Shade of the Evening.