Olivia is a character who first appeared in Episode XXVIII: Jack and the Rave as a brainwashed slave of Aku.
Olivia was the daughter of an innkeeper who was brainwashed with rave music by a minion of Aku, DJ Stylbator, into committing crimes for him as a teenager. Her father continuously tried talking to her to no avail. She was eventually freed from the DJ's control by Jack after he defeated him in battle and destroyed his brainwashing equipment.
After 50 years, an aged Olivia now takes the role of DJ and leads the new generation of teenagers to pay respect to him for freeing her and the others as well as rebelling against Aku through music. It is also revealed that she takes Jack's Shaolin Kung Fu moves as a primary music dance for her music.
Since Aku was destroyed by Jack in the past, this will cause the corruption caused by Aku on her and the ravers through the techno music to never happen. So their memory of Jack was erased as well, since Jack's help was no longer required, given Aku's evil to the future was undone. Apart from that, how her existence was affected is unknown.