Clan Verms
A former member clan of the Council of Thirteen, Clan Verms specialized in making insect swarms, giant creepy crawlies like Giant Scorpions, and producing Worm Oil. Were betrayed by Clan Pestilens during an attempt to gain more power on the Council of 13, kicked off the Council, replaced as Warbeast makers by Clan Moulder, and Clan Skryre replaced the need for Worm Oil with Warpstone Lights. Add in their swarms of invertebrate vermin were helping spread a deadly plague amongst Skavenblight, and you get a recipe for a Clan so low on the totem pole, even other Slave Clans spit on them now.