Leviathan of the Covenant (盟約のリヴァイアサン, Meiyaku no Leviathan?) is a light novel series written by Takedzuki Jou and illustrated by Nimura Yuuji.
The series is published by Kadokawa under the MF Bunko J label and has concluded with 8 volumes.
Takedzuki Jou (also romanized as Joe Takeduki) might be better known as the author of the Campione! series though his recent focus has been on Chronicle Legion.
Nimura Yuuji has also taken over illustrations for Seirei Tsukai no Blade Dance starting Volume 14.