Rebirth: Mysterious dragon emperor dxd

Follow the rebirth story of Luke and forgotten purple dragon emperor as they become the strongest pair of human and dragon in the the world of dxd. *Harem warning* The mc will not be overpowered from start and will gradually grow strong but mc is smart a slightly unique but at the same time similar fanfic for dxd. *I do not own anything which I use from other works i.e. high school dxd* * I don't own the cover, if the owner wants to get it down pls contact me and i will take it down*