Art gallery

Here is the cover

Here is the volume 4 art

Here is volume 5 art

Here is volume 6 art

Here is volume 7 art. This was never published. Basically, Ryujin was the Hell Guardian and he was going to reveal that to Kenji after Kenji accused Ame of being the Demon King's daughter (she was, he was correct, but Ryujin had to step in to stop him.)