Yenlui

The Elves worship a wide variety of deities of varying power and temperament. These beings are divided into into two main spheres of influence, with neither having dominance over the other. This is encapsulated belief of Yenlui, or balance; a philosophy that dictates that there must be a harmony between the light and dark natures of the Elven spirit.

The most widely acknowledged Elven gods are the Cadai or the gods of the Heavens, who represent the more positive characteristics of Elven culture and the natural world. These are ruled by Asuryan the greatest of the gods. In Elven belief many of the unsavory aspects of their nature and the world at large are also represented by gods known as the Cytharai, gods of the Cytharai or gods of the underworld. Of these Khaine is the most well known, being the god of murder and war.

Source
pg. 7
 * Warhammer Armies: Wood Elves (8th Edition)