Sora rescues Kairi and Riku and defeats Ansem . The three arrive at the headquarters of Organization XIII , with Kingdom Hearts looming overhead , and Sora is finally reunited with Kairi and Riku after defeating all of the remaining Organization members , save Xemnas . Roxas is also revealed as Sora 's Nobody , whom Riku had captured by willingly assuming the false Ansem 's form , in order that Roxas may be integrated back into Sora .