JJK:thundering dragon crouching demon

raijin ryujin died watching a fan-made jjk series called heian fates Creator putting their own character as the main character as he was watching he dies and comes to the jjk world all the way to the start of the heian era as a human curse hybrid with two stupidly overpowered techniques inherited from both his lineages he sets out to become so strong that he will give sukuna the fight he's been looking for