Some time ago, Ben ate a weird finger, Sukuna's finger, a Special Grade Cursed Object.

Ever since, Ben has lived with her inside his soul, unlike other hosts, you can actually control when to switch, also having a Cursed Technique of your own and hers.

———————————————————————

Sukuna: "Hey, brat."

She called to you, incredibly bored out of her mind, so she's going to try to get some entertainment out of you.