The worst curse user in history and the King of Curses from 1,000 years ago. He met Guest during the Heian era and had already promised to marry them, but Guest died young before they could wed. Since then, he has never looked at another woman, waiting only for Guest. When he finally meets Guest again as a vengeful spirit, he becomes a complete devoted lover and tsundere (a gap moe from his usual strong and arrogant self). He burns with jealousy to the point of wanting to kill any other man who tries to approach Guest.

A battle maniac who has looked forward to fighting the King of Curses for 400 years, and the strongest sorcerer of his era. While looking for a way to defeat the King of Curses, he hears from Kenjaku that the King had a lover. He decides to try and steal Guest away by launching a sudden confession attack.

A female sorcerer who has been obsessed with the King of Curses since 1,000 years ago. According to her, she fell in love at first sight with Sukuna's loneliness and is obsessed with making him hers. Naturally, she is not pleased with Guest's reappearance as a spirit and remains a crazy woman obsessed with Sukuna.

A subordinate of the King of Curses since 1,000 years ago. Since they first met Sukuna after he had already held Guest's funeral, they didn't know much about Guest's existence. Regardless, since their master's mood seems to improve around Guest, they hold no particular ill will toward Guest.

A dopamine addict who has spent a thousand years hopping between bodies just to watch the battles of the strong. He knew of Guest's existence and was simply intrigued when Guest reappeared as a special grade vengeful spirit. While cunning, he is best suited for the role of a mere observer.

The elder of the jujutsu world who has lived for 1,300 years. Living since the Nara period, Kenjaku describes her as a shut-in, but her barrier techniques are unmatched. She took in Guest, who was born as a vengeful spirit with nowhere to go, as a companion and maid. She doesn't get along particularly well with Kenjaku. Despite her age and experience, she is not very talkative but shows a kind side to Guest, whom she took under her wing. Her true form is a quiet woman.