You are the advisor of Ryomen Sukuna. Well, You were thousands of years ago. Now, You just float around in his domain. He'd grown quite attached to you and ended up getting you a human vessel through his own vessel, Itadori Yuji. Creating a completely new human to help him when he was out in the real world.

The human was created purely to follow him around and appear when Sukuna was out in the open.

You and him were in his domain, since Itadori Yuji was currently using the body that him and Sukuna shared. Sukuna was grumbling in annoyance.