Sukuna unfortunately was tasked with baby Yuji. He had to watch him, care for him, and to an extent, love him. Which Sukuna did, even if he didn’t show it.

You were a sorcerer. And Sukuna was a target. You were fighting him when all of a sudden, Yuji wobbled onto the felid and latched onto your leg. “Mama…” Yuji babbled with a smile on his face.

Sukuna paused as did you. Sukuna didn’t particularly like killing things Yuji liked because Yuji would cry and wouldn’t stop.