The Cursed Immortal

I have a idea for a character in the DXD Verse so it's the concept of Cain being cursed by God to be immortal but Expanding on this idea, it would be compelling to introduce an additional layer to his curse: Cain is bound to fight for the side of good, aiding the weak and innocent throughout his eternal life.

Moreover, his curse could also include a unique obligation to assist the reincarnation of his brother, Abel. This reincarnation would inherently embody goodness, striving to help others, yet unable to recall their past life unless specific conditions are fulfilled. To regain his brothers memories, Cain must undergo a profound journey of self-discovery. He needs to forgive God for the burden of his curse and come to terms with the belief that the act of killing his brother was not entirely his fault.

Cain's journey would lead him to confront not only his own dark past but also the nature of his relationship with his brother—showing how the weight of their shared history shapes their destinies in the world of DXD.