Suggestion for a Digimon Idea. More specifically, The Royal Knights
Issei Reborn as Gankoomon
Maybe Jaune is also Reborn as Magnamon (cause of the gold digizoid form)
What if Issei didn't believe in the flier, the granting of the wish, and threw it away, Rias not being able to arrive later. Issei is Reborn as Gankoomon (Starts as a digi-tama then timeskip to like a decade then Gankoomon) in the digital world.
Ddraig would be Hinukamuy in the idea.
Issei can be a father figure to the Royal Knights since he was a human, and a few years of survival would make him act mature like an adult.