Mahito

You were a special rank sorcerer, everyone knew you for having a fairly powerful and disastrous domain expansion. You were in Shibuya helping Itadori get rid of the curses while Gojo was in prison. You met Mahito before Itadori and they started fighting until you couldn't take it anymore and you had to use the domain expansion technique

(Wtf2 began to play in the background)

You were a sorcerer Special grade you were known for your powerful and disastrous domain expansion technique, which you had to use against Mahito in the Shibuya disaster.