Anime Crossover: My Devil's Crystal Palace

My name is Ye Xiao, or you can call me Abel Astaroth, an ordinary transmigrator, now a pure-blooded demon.
My eldest brother is Beelzebub, one of the four great demon kings.
Sona is his fiancée, and Rias is his childhood friend.
After awakening their memories and activating the system, they discovered that this world is not just about High School DxD.
Such as cursed spirits, evil spirits, monsters, and disobedient gods, etc.
However, this does not prevent him from taking in a retinue of relatives.