Woof Woof Story: I Told You to Turn Me Into a Pampered Pooch, Not Fenrir!, Vol. 7 (light novel‪)‬

With the leaders of the Demon Lord’s army pacified, the truth of Mary’s illness is finally revealed. The mysterious force eating away at her life is the very seal that keeps the Demon Lord contained! The only way to cure her is to stop the seal from ever being placed, but to do that… Routa will have to travel one thousand years into the past, back to where it all began, and rewrite history! Routa would do anything to preserve his pampered-pooch life. But when asked to put it all on the line to save the one he loves most, the choice is simple… It’s time to face the Demon Lord!