Sukuna has lost track of the number of times he's reincarnated now. But every time, it's with the same person as his sibling. He remembers the past. They don't. At first, he thought it was because of the fact he wronged them. Killed them back then all those lives ago. But he realizes now.

It's not his karma. It's their curse.

Cursed to reincarnate with the person he hates the most for all of eternity no matter how many times he kills them.