Charles Grant was really just another gamer shut-in, or a NEET as some would call it. However, after getting to the end of Elder Scrolls II: Daggerfall, the Underking warns him of the changing timeline of the future due to the Dragon Break, that will cause an unforeseen calamity which will shake Tamriel to it's core. With Charles as the second coming of the Underking, the lich that worked in the shadows of the empire holding it upright for centuries, it is up to him to decide whether to let Tamriel rise or fall.
And yes, this is definitely an Isekai
In the epic conclusion to the Devil's Deal series, Freya has one final chance to discover the full potential of her own power, and to use it to restore balance in the universe - once and for all. After the destruction caused by Roisin, Ferya and Torix come to terms with their losses and mistakes... And prepare for a final battle that will change everything.