If he did not have people around him, he would have been the same Yuji itadori that he was before Shinjuku Showdown. However, thanks to Ui Ui, Yuji could swap his body with others, and ...

Ryomen Sukuna took over Megumi's body in the Culling Game Arc. The basis for this was set quite early into the series. When Yuji Itadori died, Sukuna and he made a Binding Vow. Essentially ...