New fanfic is out you can read it.
Name: DxD: The Dragon Oppai
Summary: In a world where destiny weaves its intricate threads, Issei's life takes a remarkable turn. His sacred gear awakens at an early age, leading to intense training with Ddraig, the indomitable Welsh Dragon. But destiny has an unexpected twist in store. Issei forms an unlikely bond with Great Red, the Dragon God. As his strength grows, two captivating newcomers arrive at Kuoh Academy—a silver-haired enchantress and her azure-haired friend. Issei's heart races as he realizes his rival is the beautiful silver-haired girl.