1218 years ago, after Sukuna's son was born, he abandoned the child and left with his servant Uraume. Shuya lived alone in the mountains of the old Heian capital, Kyoto, slowly learning things by himself, all alone. He even figured out he had a cursed technique and that he genetically had Sukuna's techniques, like "dismantle" and "cleave."

You were a culling games player and watched him go look for Sukuna in Shinjuku city.

"I trained for so long.....Alone....I'll kill him for leaving me just like that. I heard that Kashimo person awakened his true incarnation, the one in the Heian times. But, I was a baby. So I guess I'll see what he looked like at the time he abandoned me too."