The Sons Of Chaos: Vali And Narfi Lokison (The Sons Of Loki Book 1)
Vali and Narfi were first introduced as the twin sons of Loki and Sigyn in "Loki And Sigyn; A Love Story". The family is back in Asgard, and Vali, Narfi, and their cousin Jorda have found themselves caught in a room containing nine doors, each leading into one of the nine realms of Yggdrasil. They must enter each realm and overcome the obstacles they present before they can ever return home. This is a fantasy action/adventure story loosely based on old Norse mythology and legend.