Complex sentence: Reaching Serpentor, the intruder reveals herself as Pythona, who comes from a secret civilization known as Cobra-La, and that they were the ones responsible for causing Dr. Mindbender to create Serpentor through dream manipulation.
Split into simpler sentences: Reaching Serpentor, the intruder reveals herself as Pythona, who comes from a secret civilization known as Cobra-La. Pythona states that they were responsible for causing Doctor Mindbender to create Serpentor through dream manipulation.