Modryn

Modryn, the Night Glens, are known collectively as a realm of Athel Loren, ruled by Lady Morlanna & Lord Arias. It is a land that lies ever in shadow. Sunlight never reaches these glades, and the only light is that emitted by the flickering spite-creatures that quarrel and frolic as they flit through the upper branches of the trees. Shaped by the perpetual gloom, the Elves and spirits of the Night Glens are spiteful even by the standards of Athel Loren. They practise magics and customs that are forbidden in other realms, and worship gods most other Wood Elves shun.

It was not always this way. The Night Glens could once have been accounted the brightest and most glorious of all Athel Loren’s realms, and its inhabitants amongst the most welcoming. All of that changed during a dark time in Athel Loren’s history, when a darkness in Ariel’s spirit spread throughout the forest. In time, the Mage Queen restored the balance in her soul, but the Night Glens never recovered.

Source

 * Warhammer Armies: Wood Elves (8th Edition) -- pg. 11