Nazarick's Devil (Male Reader x Highschool DxD)

[Author on Hiatus]
The 72nd pillar in underworld was banished and removed from all records of history after a series of conflicts between the devil leaders and the heir. The Pillar of Ooal Gown was known as the devil's strongest and mysterious magic users in all of underworld, but when the head of the pillar refused to share the secrets of his magic to the devils, they were treated as outcasts and banished to the ends of hell. How will the devils react when the former head dies and they learn that a male heir was born to take his place?