>Professor Utonium is Jack reincarnation. Jack wanted to bring back Ashi to life. So Utonium wanted to create the perfect little girl, the Chemical X is the unsentient remnants from Aku´s evil. Blosson, Bubbles and Buttercup are Ashi and other two Aku´s daughters reincarnations with all Aku´s original powers.
https://www.youtube.com/watch?v=OUvGCK9Dk34
https://www.youtube.com/watch?v=OUvGCK9Dk34