Einjerhar of Black Onyx III

is the third volume of the Einjerhar of Black Onyx light novel series, written by Akira Aihara and Illustrated by nyoro. It was released under the Dengeki Bunko Imprint in January 2014.

Synopsis
Is it a person, a world, or a god that should be destroyed? A Scandinavian dark fantasy over Ragnarok!

Lost people who boarded the world tree to prevent Ragnarok. Waiting for such a party was Avi, who was crazy for revenge. Avi tells him that he has used the power of the evil god "Mímir's Neck" to take revenge on the giant Surtr, but beside him is a mysterious Arv boy and a giant who should be an enemy. Was following ... At the end of his sad revenge, Avi runs away in search of the forbidden power "Regalun's Box", and Lost abandons his revenge after meeting his companions. Each thought is mixed, and the final battle begins here now.

(source: Bookwalker JP - Translated)