From 1d4chan

Nethu is one of the Cytharai pantheon of Elf Gods, is the keeper of the door to the underworld, Mirai, and is the head goddess Ereth Khial's son to boot.

As a door keeper he keeps a ring of silver keys on his waist. It is said making the sigil of Nethu on a piece of property belonging to an elf will gradually sap away at their soul until they waste away and Dark Elves think it is hilarious to sneak into the bedrooms of High Elf officials and put the sigil under their beds so Nethu will nab them away. They did this to a High Elf loremaster of the White Tower once and despite weeks of searching were unable to find the one responsible.

The High Elves and their gods of Warhammer Fantasy
High elf icon.jpg Characters: Eltharion - Everqueen - Teclis - Tyrion - Prince Imrik - Alith Anar High elf icon.jpg
Cadai: Asuryan - Hoeth - Isha - Kurnous - Lileath - Loec - Mathlann - Vaul
Cytharai: Addaioth - Anath Raema - Atharti - Drakira
Eldrazor - Ellinill - Ereth Khial - Estreuth - Hekarti
Hukon - Khaine - Ladrielle - Morai-Heg - Nethu
Events: The War of the Beard - The invasion of Naggaroth
Misc: Ulthuan - The Vortex - Waystone - Widowmaker
Appearances: Blood Bowl - Dreadfleet - Mordheim - Warhammer Fantasy Battle