Complex sentence: Kurumi used "The Power" to run the 100-meter dash in 3 seconds at her old school, which resulted in the Kasugas moving to the town where the series takes place.
Split into simpler sentences: Kurumi used "The Power" to run the 100-meter dash in 3 seconds at her old school. This incident was responsible for the Kasugas moving to the town where the series takes place.