Sacrifice and Promises (jjk x male!ocs)

As a first child of Daisuke family, Iori has to be a child sarcifice to prevent bad luck and desaster happen in the family while his twin, Natsuki has to be trained and became a best jujutsu sorcerer. Both of poor children didn't know what other fate will they face in the future.

But three days before the sarcifice,Natsuki let out all of his anger and kill all his family members with his unknown technique while Iori,try to stop his twin brother,make it worse. After that event,they being take under Gojo Satoru care,after he found Iori,holding unconscious Natsuki,sitting on the ground while facing their dead mother body. What will both of them face in the future while keep the promises that they can't broken whatever problems nor event happen between them??