My Adventure Romance as Noble Devil Heir in the 1950's is a Thriller, as I Expected [DxD/Fate SI]

Set in the 1950's, we'll follow the journey of a man reborn as Diodara Astaroth, the Heir of one of the Noble Pillars of the Ars Goetia. Things at it seems would not be so clear cut as it was in the anime as he'd find a whole new world populated by Demonic Pillars, Heroes wielding phantasmal weapons, and Magus's seeking his service in their journey to the Root of all Knowledge. Mixed in with your typical Cold World shenanigans of Nazi's trying to start the Fourth Reich, The games of spies in war torn and recovering Europe, and the world teetering at the edge of doom due to eldritch nukes, his journey to survive all the way to the actual start of the series would be a story all on its own.